I had a 360 first, had it for a while then sold it, bought a Ps3, i have another 360 now back in the house. My choice? Would be the PS3, why? Blu-ray for one, built in wi-fi and the games are finally improving. The 360 however has an exceptional online service in Xbox live, which the PS3 lacks (although will catch up with the recent addition of ingame messaging and soon to come "Home"), of course the 360 also has a bigger games library but with lots of mouth watering titles expected from both ends its really hard to choose between the two. I also prefer the 360 controller to the Playstations, despite having played PSX and PS2.
I know LOTs of people who have had their 360's fail although service is always impeccable and they are soon back gaming in no time (i waited a week when mines went capoot).
Your not going to be really disappointed with whatever one you get, because they will both play games and from time to time you will say oh I wish my console had that.