Depending on what you want,
Sectorlink is usually a really good choice. I have a Win2K dedicated box with them and I've been a customer of theirs for over 2 years now. They're a really straight-up company to deal with, and they'll usually respond to your emails within the hour.
Some of the harder stuff (like server config issues and getting SQL Server databases set up) takes them longer, but that's to be expected.
They still hold the all-time record for fastest resolution I've ever seen to a trouble ticket: exactly 60 seconds. It must have been a slow day for them or something, but my problem was solved in exactly 1 minute.
Anyway, they're a great bunch of people to deal with, and I wouldn't say that about just any host.
There are loads of other good hosts out there as well. Check out these sites for recommendations:
http://www.noblehosts.com (I really like this one, and the owner, a man named Artashes, is a really decent guy).
http://www.hostchart.com
http://www.betterwebhosts.com (the layout on this one's kinda bad, but the content is what you're after here anyway).