I'm a huge playstation fan, have been since a young age.
I've owned and enjoyed both systems though, so my opinion isn't a bias one.
Playstaion plusses:
- Controllers come with built in battery packs, smaller / more portable
- Bluray capability
- Free playstation membership
- Internet browsing capabilities (although limited)
Xbox plusses:
- If you do pay for xbox live, it's worth the cost (but not as noticeably as people say)
- Easy to use, family friendly interface
- Used games are everywhere, tonnes of stuff out there for xbox if you want to save a few $$
- Controllers can be used with your PC with little issues
On the other side of the fence;
Xbox negatives;
- Red ring of doom very prominent, dealt with two personally
- Scratches a ring into discs if touched while running (game will never work again unless pro repaired)
- Controllers are huge and bulky, and require either batteries or a battery pack addon
- Seems to be the console that bitching 14 year olds get for christmas, so 90% of the players are fucking lame
- Massive power supply cord that seems isn't really needed
Playstation negatives;
- The online play does suffer occasionally ( but not enough to justify paying for it, xbox live fucks up just as much at a cost!)
- The playstation store is pretty much fucked and very picky about credit cards (aka have to buy ps store cards most of the time)
In my personal experiences playstation has always been the way to go.
Again if you enjoy a certain controller type, or want a specific release then the choice is an easy one.....
Otherwise I'd go PS3 all the way, they have a great track record of using the technology at their disposal to the best level possible, and making a quality system that lasts for a good many years.