I'm in the same boat as the OP. I'm getting my tax rebate. I had a 360 but I sold it before going back to grad school, but man I'm itching for videogames again. Sooo....
360
Street Fighter 4
Gears of War 2
Fallout 3
Resident Evil 5
Halo 3 ODST
360 is the least expensive (I can get one on ebay for 140, not as reliable-my old one red-ringed but sold the replacement, never used it to play online)
PS3
Street Fighter 4
Killzone 2
Fallout 3
Metal Gear Solid 4: Guns of the Patriots
Resistance: Fall of Man
Resistance 2
Resident Evil 5
God of War 3
I was a halo fan but I'm kinda burnt out on it and looking forward to playing Resistence, MGS4, and Killzone are the games I'm looking forward to. Plus us in the US can get them used for about $30 which negates the whole $60 for a new game. Also I truly don't see myself paying for xbox live nor do I wanna buy the wireless attachment so all in all the PS3 seems like system I am leaning on. Looking on ebay and used sites and I can buy a PS3 for about 270-300. I'm honestly surprised that I am leaning on the PS3 as it cost much more, but yeah, hopefully I don't regret this.