LiquidWeb seems to offer about the best support I have seen. The planet is alright but most of the staff makes like $10 per hour so if you have a serious problem it is not always resolved quickly the first time.

I have never had issues with liquidweb except for their billing / sales system but thats minor... they get my vote.

The Planet (Texas) and viaVerio (Orem). Outstanding DC's with all the trimmings.

Savvis or The Planet