I have all current gen systems. Here are the Pros and Cons of both the 360 and the PS3 (IMO). Both systems have very similar graphics.
PS3:
+The best Bluray player.
+Free Online.
+Controller with the best D-pad (better for fighting games).
+PS1/PS2 Backwards compatability (only on the 20 GB, 60 GB and old 80 GB models).
+The ability to upgrade your hard drive using a standard laptop hard drive (up to 600 GB).
+Linux support.
+PS3 exclusives: Resistance series, MGS4, Little Big Planet, Killzone 2.
-Most games are ported from the 360 to the PS3 and with a few exceptions, they run worse than on the 360 (see Fallout 3 PS3, Bioshock).
-For new games Online is very buggy and it's missing a lot of features that live has.
-A lot of the older games don't have trophy support (achievements)
-The 40 GB PS3 and the new 80 GB are not PS2 backward compatible (they're still PS1 compatible)
-games take longer to load, or require huge installs for them to load fast
360:
+Xbox live.
+All games have achievements.
+Controller best for FPSs.
+Huge online community.
+ or - A lot of people have mics.
+Exclusives: Gears of War series, Halo 3, Lots of JRPGs, Fable 2.
+very stable online.
-RROD
-You have to pay for live (about $50-$80 a year)
-horrible d-pad
-lots of immature children, and adults
-you can only buy microsoft's hard drives to upgrade the 360 hard drive.