x-arioch: I am not a convert but returning back to PC gaming. About 10 years ago I used to game on PC most of the time and played stuff on the PS1. Since the PS2 I had been doing more console gaming as more and better games were available. Up until a few months ago, I hadn't gamed on a PC for almost 2 years.
Cost is the big reason. For as much as people complain about the cost of a PS3, it is less than a high end video card ( or a cheap desktop PC with a passable card ). On a console you never have to worry about compatibility or driver problems. The games just work. I currently have a PS3 and game on it about once a week.
The thing that got me back to PC gaming was a combination of Left 4 Dead, Steam, and GOG. Being able to get decent games, cheaply priced, that run well on a sane PC, without having to leave the house ( or worry about what time of day it is ). Digital distribution rocks!!
I am really enjoying Freespace 2 and Fallout 2 ( both from GOG ), I played the first in each series, but never got around to the sequels ( actually I have fallout 3 on PS3 ).

Weclock: $80 is worth more than a $400 ps3?
seriously, a ~$500 gaming pc can PWN crisis which is supposedly "the highest end out there."
http://game-central.org/2009/editorials/how-to-build-a-sub-500-gaming-pc/ I personally spent $80 on a video card that gets me the ability to play crisis just fine in my monitors native resolution (1600x900)
I am guessing that you have a very different idea of what is acceptable when it comes to gaming hardware. The cost effectiveness of a console is pretty hard to beat. I only need to buy a new console about every 8 years or so to run the latest games, which kills the update cycle on PC hardware. I used to buy a new $150 video card every 18 months just hoping to be able to run the current games, that is $1200 over 8 years, just for the video cards.
I can't run anything using the Crytek engine on my current laptop, which was $1000 just last fall. Mass Effect looks comical on it, running at 10-12 fps. But Mass Effect on the 360 is fine, and FarCry 2 on the PS3 looks great. I can't imaging running the new "Prince of Persia" or "Assassin's Creed" on the $500 pc and being happy with the video performance. They run flawlessly on a PS3 or an X360.
For those that think the PS3 is just a sub $50 video card, you really need to study some computer architecture. It may only have a cheap video card, but it has an array of cell processors to function as the GPUs and it has a bus speed about 10x faster than any PC I have ever heard of.
.... All of that said, I would still rather game on a PC most of the time. Historically, most of the really good games were developed for PC.