Against zerg, I never have 1 rax then a refinery. I go 2 rax, and pump out marines and add some more barracks. This is my BO:
8th SCV build supply
9th mine
10th scout
Build 1st rax with SCV that finished supply
11th - 12th 2nd rax
SCVs
2nd supply usually at 14 or 15
Academy
More rax
You have to pump out marines as soon as the 1st rax is done, while still building workers. If you have some decent micro, you can beat an early ling rush, and then zerg is most likely screwed, so you can storm in with a few marines.
Another strategy that I only use for 1v1, and that's really fun and effective, though risky, is the proxy build. It goes like this:
SCVs
8th SCV supply
9th mine
10th bring both this SCV and the SCV that finished the supply to nearby the enemy base (or the middle of the map). Build 2 rax while still creating SCVs at home.
2nd supply at around 13 or 14
When 1 of the rax are done go scout. Pump out marines, then rush when you feel right. If he attacks your base with his early ling rush, use your SCVs to attack, and counter with your marines. Build some more barracks if the first rush doesn't work. Hopefully you win.
When proxying, very importantly you have to make sure your opponent doesn't see your 2 SCVs, otherwise he'll know, and you're screwed. And put your barracks in a place the zerg will most likely not notice (quite obvious).
I'm considered a newb on Bnet, so if any of these strategies/bos suck, let me know.
Hopefully this helped you out.
None.