As a owner of both consoles I say the Xbox360.
Large library of games most of them better then on the PS3 were the common problem is long loading times and frame rate issues.
The controller is nicer on the Xbox360 even tho the sixaxis is pretty sweet when implemented right.
The main thing that the PS3 has going for it is that it's "live" is free which is very nice indeed but Xbox live despite the price(which is cheap if you compare to let say MMORPG monthly fees) is better then PS3.
Just downloading DLCs is just such a difference in speed. It took me 10 minutes to download a 10mb patch on PS3, the same size would only take a minute or 2 on Xbox live on the same connection.
Of course you can't argue with the actual price of the console where the Xbox360 goes for the same price as a Wii and the PS3 costs almost as much as 2 Xbox360s.

Reliability of course is still a problem with the 360 but with the latest hardware it is more quiet, cooler and more reliable(PS3 is of course more quiet, cooler and reliable).
Problem with RRoD is there still but they have increase the lifespan of it and the latest hardware that should come out in august or so should get rid of the problem for good(well according to guesses by the experts).
Naturally this is provided that you take care of your Xbox, keeping it in a unstable and enclosed area is a one way road to RRoD or other issues.
Keep it on a stable table where air can flow freely and you should have no problem.

If you are short on cash then Xbox360.
Got lots of money ?? Get a xbox360 and buy more games to it.