FPS games need the keyboard and mouse. I wonder why there is no keyboard/mouse packages for consoles or the ability to use any usb keyboard/mouse. Racing games on the other hand are much more fun with the pad. I've preferred PC as a gaming platform but to get a good gaming pc costs a lot more than xbox360 so when my pc got too old to play anything new I bought xbox360.
I don't think the online play is so good. I really miss the keyboard when writing to other players. I know there is one, just need to buy it. I also miss the global chat which almost all pc games have. It's so much easier than just to press a key and write your message and everybody sees it than with xbox where you have to select a friend, select message, select text, write it, select send... blaa blaa blaa. There might be a quicker way but I don't know it.
Voice is also very bad since I can't use my own headset with it and when I plug in the xbox headset the other audio is still on my own headset...who idiot invented that feature.
Overall, I'm happy playing single player games with xbox but the user interface and the things mentioned above brings the online experience down a lot.