I got a decent steering wheel as a pressie from the Mrs it's called Micro CON 2 comes with the pedals and flappy padal for gear shifts, she also bought me the X-rocker chair which is absolutely ace, 2 speakers and a sub built in, it's awesome and very comfy.
That said, if I bought the Kinnect it wouldn't be quite worth it for me as I love these 2 add ons and wouldn't really be able to use them with the Kinnect.