I have a friend who has around USD$650 and would like a desktop computer. Is it possible to get a PC for that much with 4GB RAM and a semi-decent graphics card (enough to do a bit of 3D modeling)? He needs screen and keyboard and mouse as well as the usual chassis and interiors.

Quote from Jack[RCDF

a semi-decent graphics card (enough to do a bit of 3D modeling)? He needs screen and keyboard and mouse as well as the usual chassis and interiors.

Hmm... I'm not familiar with how well the gaming cards fare with workstation software, but you can Google around for it. With Monitor/Keyboard/Mouse in the cost, however, this'll be tough.

Having to buy a screen with that amount is going to be pushing it. Unless he went with an old CRT which he can get practically for free off trademe.

Quote from Lanthanide

Having to buy a screen with that amount is going to be pushing it. Unless he went with an old CRT which he can get practically for free off trademe.

Second hand LCD would be fine, same for mouse and keyboard for that matter, but CRT won't fit on his desk, not with a keyboard as well. If it goes over the price a little that'd probably be fine.

Probably he should get the LCD, keyboard/mouse first and then tell us how much money is left. Of course talking in $US is kinda pointless, but I guess they can give a rough outline and you can check out prices on pricespy.

If he doesn't mind spending a little extra on the monitor for picture quality, there are a couple of LCD displays for under $200 that have both an IPS panel and LED backlight. I'm not sure if the LED backlight makes much of a difference, but the IPS panels look a lot better than the cheaper TN panels that almost all monitors even at this price point have.

The Asus VS229H-P is one such monitor with IPS and LED. It is 21.5 inches and costs $164 from Amazon in the USA. Like probably all other cheap LCD monitors, it has been reported to have some backlight bleed at one of the corners or edges (conversely, my $270 ViewSonic VP2365wb has absolutely no backlight bleed). It is stated to have 14 ms response time, but my IPS monitor says that, too, and I can't tell the difference in response time between it and my Asus VH226H when comparing side-by-side with the same games cloned to both displays.

There is also the ViewSonic VX2336S with IPS and LED. It is 23 inches and costs $183 from Amazon in the USA. I haven't seen any professional reviews on it and I've only seen one customer review for it, but it didn't mention anything about backlight bleed, so there's a chance it might not have any that is particularly visible. It does not have built-in speakers, but that probably isn't important. There's a chance that since it is from ViewSonic like mine that it could potentially be as good or nearly as good as my $270 ViewSonic 23 inch IPS LCD from a year ago, other than that it doesn't have an adjustable stand with it.

US/CA/NZ? I forget where you are Jack, and you said USD so I'm thinking US at least for the friend. Lemme see what I can do.

Edit: done in US:

Part list permalink / Part price breakdown by merchant

CPU: AMD Phenom II X4 830 2.8GHz Quad-Core Processor ($89.99 @ Newegg)
Motherboard: Biostar A880G+ Micro ATX AM3 Motherboard ($49.99 @ Newegg)
Memory: Corsair XMS3 8GB (2 x 4GB) DDR3-1333 Memory ($34.99 @ Newegg)
Hard Drive: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($82.99 @ SuperBiiz)
Video Card: HIS Radeon HD 6870 1GB Video Card ($157.55 @ Newegg)
Case: NZXT Gamma Classic (Black) ATX Mid Tower Case ($33.99 @ Amazon)
Power Supply: Corsair 430W ATX12V Power Supply ($36.98 @ Newegg)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($18.99 @ Newegg)
Monitor: Hannspree HF225DPB 21.5" Monitor ($118.99 @ Mac Connection)
Keyboard: Lite-On SK-1688U/B Wired Standard Keyboard ($14.97 @ Newegg)
Mouse: Gigabyte GM-M6880 Wired Laser Mouse ($22.98 @ Newegg)
Total: $662.41
(Prices include shipping and discounts when available.)
(Generated 2012-01-25 12:48 EST-0500)

He's in new zealand, same as me. Aaaand after checking half those items at http://www.pricespy.co.nz the prices for a lot of it are a fair bit higher in NZD. D:
In NZD he's got $800. Pricespy is great for finding parts, I just don't know enough to tell whether a part is good or bad vs other parts at similar prices.

Yes, I think the way to go with this is either Ex or someone else to use pricespy to see what prices/parts are there, or for general brand recommendations to be made based on US sites and then see if its worth purchasing in NZ.

I can't really help you Jack, since my mum works for a computer hardware distributor I just buy everything through her at dealer prices which are cheaper than anything on pricespy. So my selection of brands to choose from is significantly reduced.

Here's a vague description of what you want for $650 USD. Try to make it fit for yourself in NZ.

A z68 or p67 motherboard. Look for UEFI instead of bios. Good manufacturers, in my order of preference would be Asus, msi, biostar, gigabyte (no uefi). Others exist, price is the big factor here.
An intel Sandy Bridge processor. minimum is i3 2100. maximum is i5 2500k or e3-1220 (a server processor). Buy this last, make it fit your budget. Try to avoid buying simple higher clock speeds, if a lower clock speed exists and is significantly cheaper, get it. $20 for a 5% increase in speed is not worth it.
Any DDR3 ram you can find at the cheapest possible price. Try to balance speed with the price, but it's not important. Heat spreaders do nothing except increase the cost and look cool.
Any HDD you can find at the cheapest possible price (look around for cheap ones from any store, doesn't matter if ebay or whatever). Don't try to get huge storage capabilities. Save up for an SSD later.
Any manufacturer graphics card of: 6870, gtx 560 Ti, 6950 (1 GB or 2 GB). Balance this with the CPU so that you fit your budget.
PSU - look for decent manufacturers (Antec, Corsair, Enermax, Super Flower, Seasonic, a few more) first. Double check your choice on the PSU review database for its authenticity and likelihood to break/destroy your computer. depending on the graphics you choose, you will want anywhere from 450W to 650W. 500W should be able to run everything just fine, but personally I would stick with a 500w, 6870, i3 2100 or some other i5.
Case - get something you think looks good and fits your budget. If you go super super cheap, you won't be disappointed. If you spend $100 on a case and it's not 100% perfect, you will be disappointed.

This is actually the generic metric I go for when I create a build. The more money you have, the more you can spend on each part, making the overall computer better, but not linearly faster. The minimum computer you should be buying is an i3 2100 with a 6870. the maximum you should be buying is an i5 2500k with a 6950 2 GB. That goes for all price ranges. If you want to go cheaper you should save up longer. If you want to go more expensive you need to get a life.

If you really must go cheaper, then the AMD route is the way to go with a 6850.

http://pricespy.co.nz/category.php?l=s84094125&cols=774,5620,1870&o=produkt_pris_inkmoms#prodlista
What am I looking for here? I know very little about PSUs, those all seem to fit but I don't want to just choose the cheapest one and some don't have much info on that PSU review database you linked to.

http://pricespy.co.nz/category.php?l=s84094198&cols=574,783,615&o=produkt_pris_inkmoms#prodlista
much the same here. If the answer is simply "do more research" then that's fine but if there's obviously better or worse mobos and PSUs there then it'd be good to know.

Well the PSU database has a large number of reviews, but if you look carefully, you'll notice that 90% of the reviews are positive for all those companies listed in the pricespy. The other 10% is just mediocre. I don't think any of them failed. I would probably pick the enermax tomahawk just because I like enermax, but search around and see if there's a good price on anything else, then double check the database for reviews. If it has no/few reviews, take a look at the other reviews for the brand. If there are any fails/bad recommendations, you can assume that any unreviewed power supply made by the same company is bad.

For motherboards it matters less. I would recommend getting a motherboard with UEFI, so gigabyte is out (though they make good motherboards). MSI (excalibur will tell you to avoid them due to getting 3 RMAs) is also typically good. Asus and Asrock (both made by the same company) are good. Biostar used to be pretty bad, but is getting better. ECS is still iffy. To pick a motherboard, figure out what you need on it (usb ports, pci express, onboard video, sata II or III, size, power) and match anything made by a decent company. If you're not overclocking, I don't see why you would need anything more than the cheapest motherboard with an h61 chipset, but you may need something else that only a p67 will give you.