The popularity of MMOs on PCs can not be denied, in nearly all the PC market. The new Lord of the Rings online MMO is set to become the second most popular game behind WoW and is growing the market and not stealing from it. Also, believe it or not the PC is getting tons of console ports these days. Many games are finding their way to PC because there is a (I believe) growing market of dedicated gamers. When the vast majority of your budget is in the art assets it just makes since to spread out onto as much platforms as possible. I think the PC is benefiting from 1.) Console game developing hitting extreme highs. 2.) Explosion in markets that show PC gamers are willing to pay. 3.) Extremely aggressive pricing for computer equipment.
To be honest I don't care what a "report" says. I think PC gaming will continue to expand in a large number of markets and areas, including the US. The only issues I seen hurting it are the lack of value that consoles gamers are experienced to heading to PC (this is why Live for PC won't work, it costs money for WORSE service then we get already) and piracy, but if your game is good it has shown that people will buy it.