Shooters and FPS's: Xbox 360, you got the ever popular halo, Gears of War and even more block buster shooting titles coming out frequently. If you are interested in shooters put your money on 360, because this is the only genre PS3 will lack in. Sure you got SOCOM and Call of Duty (which is 3rd party) but what else.
RPG's : PS3, so Xbox 360 has
some support from square but that may only be temporary if sales like this keep up in Japan. PS3 is guarenteed to hit big in Japan along with dedicated support from square, atlus, namco etc.
Graphics: PS3, while it's graphics may not be as far ahead of 360 as sony claims, it still will be a noticibly more powerful conosle. Think Xbox graphics (PS3) to PS2's graphic's (360), halo didn't look to different from MGS2 but as time went on you saw how much better Xbox's (PS3's) graphics really were compared to PS2's (360's).
3rd party support: PS3, nearly all the game companies that worked on the PS2 will be making new games or sequels for the PS3 (except for Itagaki who moved to the xbox shortly after it's launch). Xbox 360 has a good bit more 3rd party support than Xbox but it still has some ways to go before surpasses PS3.
Backwards Compatibility: PS3, all of Playstation's and PS2's games will be playable on PS3 without the need of a hard drive. 360 requires a hard drive to play xbox games and it can't play all of them (say buh bye to munches oddysey, oddworld strangers wrath, Jet Set Radio Future, and sob
...half life 2). Many gamers along with my friend (Jason) complain about random glitches such as ghosting in halo 2.
Storage medium: PS3, this is what caused me to skip 360 (eventhough it was hard to part with halo and half-life 2). PS3 will be using a more efficient blu-ray storage medium which will be needed to make games a couple years down the road. Microsoft wanted to launch 360 earlier in an attempt to get a head start in the competition, however because of this early launch they were not able to include an HD-DVD or blu-ray player in their console. This is what might hurt them a couple years in the future when one of these formats become a neccesity. They could have launched all the consoles with the hard drive and update later with a hard drive patch but the core package negated this.
Online: Xbox 360, eventhough Ken Kutagari and crew are planning a centralized online service nothing is totally solid. PS3 will still have online play (and it's free too) but it won't be like live. Xbox 360 has live a solid online service which will live on in the next generation (too bad it's $50.00 a year, well it's still less than cell phone bills).
Price: Xbox 360 and PS3 are both pretty expensive. PS3's price is yet to be announced but many expect a $400.00 price tag with sony taking an intense loss for the first couple years. Howard Stringer president of Playstation marketing said expect it to launch anywhere from $300.00-$400.00. If it launches at that price you actually get a better deal than purchasing a 360, due to blu-ray player and cell chip costing near that price together. Not to mention blu-ray players will cost near $1,000.00 so you are actually getting one for less than half-price.
My Reccomendation: wait for PS3, if you can live without a phenomenal shooter like halo or centralized online play, PS3 will be a much better console with outstanding support and future potential. The thing is that you wanted your next console mainly for FPS's in which 360 beats the crap out of PS3.
