We can't explain the universe, just describe it; and we don't know whether our theories are true, we just know they're not wrong. >Harald Lesch
Impressive low-budget from Roy.
Though it cuts corners I wouldn't recommend. Your alternative build tells me you recognize the dilemma. I suggest to save more money for a few months and buy a more expensive build then, or leave out optional components for now (better cooling, SSD, graphics card, 4gb RAM, case, heck even optical) and buy it as money comes available and have a better, more satisfying build in the long run.
Watercooling is not quieter than air cooling. If anything, the pump is more audible because it's outside the case. But it can potentially dissipate more heat so it's particularly interesting for overclocking and enthusiasts. Since you're not going for a high performance build, air coolers should be fine.
Though watch out for stock AMD coolers they tend to blare like turbines. But I can't tell you which models do and which are fine.
Intel stock coolers are non-audible in idle, but they become clearly noticeable when the CPU has a lot of work to do.
Consider skipping the GPU for now. An Intel HD 4600 should be enough for today's games on medium. And the longer you can wait the faster GPUs will be for the same cost, effectively prolonging the viability of your build.
AMDs are fine performance wise; they even offer a better bang for the buck. Though their best bang will not be quite as loud as Intel's, they can easily satisfy the demands of the average user. Their main problem is efficiency. They need much more power per performance than Intel CPUs, which generates more excess heat. And that ramps up electricity cost and cooling demands and shortens lifespan. That's why they are considered inferior, but they are still viable where budget is tight.
Haven't read up on hybrid SSDs. Though I imagine it's quite effective when you're usually accessing the same files and quickly fades in effectiveness when every day you work with different programs, large files, games, etc., because then the cache won't be able to predict what to cache. (completely talking out of my ass here)
The sweet spot for SSD size is 128, the minimum size 64, if you really, really have to save $20
As for using a tiny SSD as cache without going hybrid, I wouldn't know why you'd want that, but Windows 7 and higher can use USB drives to speed up the system, so it should be possible to integrate a SSD. However it makes much more sense to just install the OS on it.
Note that Amazon.com offers
the same CPU for $160 when choosing a different seller.