Right now .. 360.
A few months from now .. most likely a PS3.
I have both ... hate the PS3 controller and the games for it (at the moment) except for cross platform stuff which I own on 360 anyway. I primarily got the PS3 for BR playback but the fact that I can game with it is nice, I just don't.
I recently had a tough decision to make myself as I recently put together a dedicated driving game setup (chair, wheel, console, LCD TV, buttkicker, surround sound, etc) and had to decide to go 360 or PS3.
I REALLY, REALLY, REALLY wanted to go PS3 and get the Logitech G25 wheel. That's what I wanted and that's what I decided on but in the end I got the a 360 instead. Here is why ....
PS3 - $400 (cheapest I could get new, used maybe $300 if I got lucky) / XBOX 360 -- cost me about $100 used as I got a package deal and sold off all the extras that came with it
Wheel - went with the MS Wireless wheel since I got it for X-mas and couldn't return it(this was kind of the thing that pushed me towards the 360)
Logitech G25 - best deal I could find was $265 shipped (OUCH!!)
Game Selection -- 360 killed the PS3 for me here. I know, I know everyone says wait for GT5 it will blow you away. Well if the game is anything like the demo then no thanks -- I didn't care for the demo at all. Forza 2 IMHO kicks a$$. I may get proven wrong and GT5 be the end all be all but for me I love what the 360 had to offer for driving (Forza 2, PGR3 & PGR4 -- cross platforms I have DIRT, NFSMW, Burnout Revenge, Nascar 08)
If I had to decide again in a few months the decision may change but for now 360 is where its at for me.
Lucky for me I do have both. I would think get a Falcon based 360 now and game away. Get a PS3 bundle with the new DS3 and MGS4 and enjoy both worlds.
My game systems now are -- (2) 360s - 1 HALO edition, 1 Falcon, (1) PS3 40gb model. I no longer game on my PC -- I miss this a little but I got tired of all the endless compatability BS and constant costly upgrades.
Greg