My 360: It's quick - By the time i've sat down, gotten comfortable and flicked the TV on, it's ready to go! Second, i like it's comfort and simplicity - You put the game in and tap the go button all from the comfort of you couch. Slip your headset on, invite a friend to a chat and you're good to go with VOIP. Lastly, it's cheap - the 360 is extremely cheap to buy and the gaming quality you get out of it for how old and cheap it is really is quite fantastic.
My PS3: BluRay - Hello hi-def movies and gaming console in one! Browser - It's great to be able to show friends hilarious Youtube clips from the comfort and accessibility of your lounge room. Power - Whilst i've always been a fan of my 360 moreso, i've certainly seen the PS3 push out some brilliant graphics and it's a platform that is constantly being mastered by developers who are harnessing more and more power out of it's potential.
What do you like about yours?