I've used only terran, once as protoss to test something with a friend, but aside from that, all terran. my rec is 34-18, so minus the ten games i played yesterday, i was able to squeeze out 42 today. The matches can end really quick, i've only had one "long" game which was a tvz of like 20 or so minutes.
Marines are crazy good with stim/hp upgrade, and a few marauders tagging along does really well. Then you get medivacs and you can do marine/marauder drops all over the place since medivacs move really fast.
After getting a little more used to the game, every matchup consisted of me going some variation of marines/marauders/medivacs. that combo, mixed with a few other units, is really good all around currently, until the game evolves a bit more and people get better.
The one unit i've found very litte use of is the hellion. Sure it's fast, has splash and does good damage vs. things like zerglings or workers, but they have no real purpose. as a meatshield for tanks, marauders/marines are way better. for worker harassing there's reapers or medivac drops, and reapers do 40ish damage to buildings. the only time i found hellions to be useful was in tvz, i went fast two fact with one reactor add-on and shat out a good sized bunch of them and harassed the zerg. He wasn't very good, so it's tough to say if it was even worth it.
It's after 5 am so I'm not doing a very good job of properly projecting my thoughts about the game thus far. I'll end it with the game is tons of fun to play, and that's having only experienced being terran.
Oh and ghosts in tvp are hilarious, emp>protoss.