I want to second this recommendation. I started looking at these after it got the nod from stigz, and while I haven't had a chance to plug this up to my gaming rig, I did become completely absorbed in GT5 last night on my PS3. The experience is completely different with this wheel.
I was a doubter without question, as I once purchased a Thurstmaster Formula T2; which was quite popular back in the day, but it always seemed lacking to me.
The Driving Force GT is an entirely different world, and takes the driving experience to the next level. Most definitely a game changer! Had to watch several for a decent deal, but ended up picking it up used on ebay for $75 USD including shipping.
Looks like I'll be building a mount so I can incorporate it into the rotation on ToddZilla.