$400 for a PC "it runs" on doesn't = $400/$300 console that runs a game the way it was coded to run. running a game with tearing and slide show framerates in low resolutions don't equate to what the game was designed and envisioned to look/perform like. it's one of the main reasons that PC gaming is so frustrating (without the funds) and why it's still not so easy to compare them to consoles.
also, you'd spend that money on the console once (hopefully). controllers, the games, online, whatever, would be your continued spending after the hardware purchase. PC's that run their respective games (ie: the games coming out around the time you purchase/build your machine) require far more than $400 to run WELL and the way they were intended. then a year later the games coming out are making your machine sweat, you're seeing tearing and framerate problems, or you can't turn all the new bells and whistles on, and then the next year you're having to upgrade again.
im having a hard time understanding why few find it amazing that sony is actually selling PS3 at the current rate for the $400 they're still charging for it. not best doesn't = bad. they're doing well for the price. publishers want to sell more units, and that's fine, but if a lot of these new PS3 sales from a price drop are existing 360 owners, what are they going to complain about IF the PS3 versions of these games don't jump up in sales as high as they expected?