I've been with a lot of different hosts, and I must say, GamingDeluxe is by far the best one. The support is excellent, the service and network is superb too! I especially love the "personal" support you get when you talk to support, you can like shit-chat about stuff, and they're OK with it, you don't get any macros smashed in your face when you describe your problem, and often, they know the easy fix for it too.
I've got a R210VII as recommended by Carnage (and Smiths :p), and it's probably the most powerful server i've been operating, it's extremely fast, it's CPU holds up with whatever load you throw on it and the best part about it? It's dirt cheap for such an amazing machine.
My experience with GamingDeluxe is awesome, I couldn't be more happy, really.
Mike /w BlackOutGaming.org