I think the Xbox supplements my gaming experience. But PC still is my main platform.
I think it matters by what types of games you are into. If you're into FPS games, RTS, and even RPG's, PC is probably the way to go. But if you are only into Sports, Action-Fighting games, and racing games, Consoles are the way to go.
Luckily, my tastes are fairly broad, and so is my credit card debt

. I tend to only play sports/racing games for xbox, and everything else on PC.
I don't think xbox is killing pc gaming, I think it supplements it, depending on the person's taste.
But that's just based on me, how does it effect overall? I think it took away some developers who were mainly for PC, and gave us the results of bad console ports (DX, HALO, and others)
Maybe with this new XNA from microsoft, that will free up time and let developers be able to customize for each platform, without costing any extra money and time.