I have a few questions to you before I can make a recommendation. What is your budget? Do you need managed servers? Do you need to be able to call the company at 2 AM?
If you have a lot of requirements and don't mind paying the premium, I would recommend Singlehop. I haven't personally used it, I have a friend who raves about it on and on. I think at Singlehop they help you manage your server as well as traditional datacenter work.
If you just want a budget box (beware that they use desktop CPUs), Joe's Datacenter is by far the best budget provider I've used. Joe's has gone down once for me, and they've emailed me in advance for their 15 minute downtime.
But, please, get back to us with details as I really love talking about data centers!