The PS3 and the 360 each have their ups and downs.
> PS3
Pros:
-Better graphics (don't be a faggot and say otherwise, it's been proven)
-Console Longevity (doesn't burn in hell like the 360 every two months)
-PlayStation Home (though I see this as entirely pointless and a complete ripoff of Second Life, and I don't approve of Sony stealing Nintendo's Mii idea)
-Online=Free (Not a single PS3 title requires a monthly fee to be played online, and for most online gamers out there, this is orgasmic)
-Console Exclusives (A lot of the Sony exclusives are simply awesome, like MGS4, Uncharted: Drake's Fortune, Little Big Planet, as well as future exclsuves like Killzone 2 [which, its predecessor was considered the Halo-killer], and inFAMOUS)
-Price Drops (though there won't be one this Christmas, there will be one soon after, which will be helpful).
-Downloadable Content (Now Microsoft has their work cut out for them, with Sony catching on to the multi-player scene)
-Gaming Library (Though it's not as solid or depth-y as the 360's, developers are catching on, and that means there will be even more exclusives.)
-Connects to PSP (only relevant if you own a PS3 and are happy with their shitty lineup of games)
-Blu-Ray (This is the main thing that allows for better graphics in the system.
-Processing Cell (7 active, 1 for redundancy. Why is this good? Because of its 7 core architecture, Cell allows developers to designate each core to a specific task. More sparks, more people, more physics, better AI, more particles, more of everything at the same time on the same HD TV.)
-3rd Party Support (PS3 has an extensive amount of 3rd party supporters from all over the world. It is the most supported system out of the three consoles. This probably means, more games, more innovations, etc)
-Hard Drives (This means that developers will be able to use the hard drives to drive gameplay or to speed up and reduce load time.)
Cons:
-EXPENSIVE WHAT THE FUCK
-Big and ugly design (can't wait for the slim-line)
-Processing Cell (This sucker makes it super difficult to develop for)
-NO RUMBLE
> 360
Pros:
-Broader Library (Yes, it's a year older than the PS3 and has a hugeeeeeee library)
-Higher-quality games (in my opinion, Gears of War and Halo 3 are considered high quality. I don't even like the 360)
-Xbox Live (even though you must pay for it, you can see what friends are online, send them messages [voice and text], and jump right into a game with them.)
-Price tag ($100-200 less for a gaming experience? Hell yeah.)
-Better graphics than the Wii >_>
-Live Marketplace
-Solid exclusive titles (GoW2, which is essentially the same game as 1.)
Cons:
-Red ring of death (you die nao)
-Overheats easily
I admit that I'm not as well-read on the 360 as I am on the PS3, but if anyone has anything else to add, feel free to do so.