I think we can finally say that PC Gaming is dead. Outside of a few hot games that are coming down the pipe, Fallout 3 and of course Spore, there is really nothing out there that makes you think, "I really need to upgrade my PC". The PS3 and the 360 of effectively put an end to the nearly constant need to upgrade your PC just to keep your spurs. With the cost of even a ho hum machine cost 2x to 3x that of a PS3 or a 360, its just not cost effective.
The first area where PCs are really taking a hit is in power usage. My current PC is about 3 years old, a homebuilt AMD 3200+ with 2GB of RAM and WinXP. Runs all my games fine, but to be honest I cant remember the last time I played a game on my PC. The power supply is about 350 watts so its small compared to some of the 800-1000 watt behemouths out there. This summer I decided to stop doing BOINC apps on my PC so I could save power, and in just 3 months I have cut my power usage by an average of 50%-60%. And this is just a low power need PC, Some of the new high end PCs require power supplies of 800 watts or more. Hopefully your not running something like this more than 12 hours a day, it could break the bank.
The PS3 and the 360 are quite low in power usage for what you get, usually in the 300 watt range.
Another area is hardware. You can easily spend $500 every year or 2 just to keep up, not to mention try to keep ahead. New video cards coming out every year, and a lot of times you need to add other things to take advantage of that power. At least with the next gen consoles you know you have the best you can have, no need to worry.
People are getting tired of having to spend money and time just trying to stay current. If Spore where not coming out this year, it would be a very bad year for PC Gaming.