So, I decided to do my placements for 1v1 tonight. I won 3 and lost 2. I've mostly been playing with a Barracks being started at 9, supply depot at 10 and usually using an early marine push (usually not against Terran).
The games I lost... I pretty much made stupid decisions with my barracks placement. In the one, I placed it at the bottom of my ramp after seeing it done before... well, I learned the hard way that it's not really a good idea at all. Maybe versus Zerg, but other than that, not so much. The other time I placed my barracks at the wrong ramp >_>. In that game, I simply got out-Marine'd at the beginning. I still survived by moving my command center to my nat and eventually taking them out, but it was GG from the huge loss in eco :\.
I won two games against Protoss Void Ray rushers. The one didn't wall off and I just annihilated him with two Marine pushes. He only had a few Zealots and I just micro'd them down with a little run-n-gun. The other was a bit more formidable. He had a few cannons near his ramp, so I had to retreat with my initial marine push. I gained a few tanks and used sweeps to gain sight of the cannons and I blew most of them up. When the last pylon was in the red, I pushed my units up the ramp and took it and his force out. I ended up losing everything but one tank and a marauder, so I pulled back and he gave chase with a dastardly Void Ray. But, he quickly retreated when he saw I made some more Marines!
I ended up winning with a push into his base using a few tanks, marauders and marines. He thought he could get me at this time... but I knew he'd be up to no good! I set the rally point for a few of my barracks near the top of my base and surely enough, he sent a fleet of Void Rays up there. Upon their destruction, it was GG!
Once I clean up my act a bit, I think it'll be a bit better!
EDIT:
Good rushers are the worst. Even if you scout it in time, all you did is prevent yourself from auto-losing. Now you have to dig yourself out of a hole.
I almost always play like someone is going to rush me, unless the map is just really long and I have more time simply because of the walking distance. But as I mentioned, I usually build my barracks first and make sure to get around 4-6 marines to hold up behind my Terran Wall of Cheese!