Personally, I use singlehop.com
They have 24 hour phone, email, and chat support. I have literally called them at 3:30 in the morning.
You get a dedicated server - with or without a system admin.
You even have a dedicated account manager - so you have the same person to yell at if you want to.
I've been through some of the big boys (mentioned here) but I love this company.