I second the vote for 3Essentials.  I've had a few other hosts in the past and have been extremely pleased with the responsiveness of the support team at 3Essentials.  I've never been left with a bad taste with any issues over there.  They rock.

This makes 3 for 3essentials. Please use my refer if your interested:

3Essentials Hosting

If you're knowledgable about servers and DNN then many of the mentioned hosters will probably work for you.

If, however, you may need some DNN or server side issue support I recommend PowerDNN.

Some of the things I would check with any hoster would be:

• Can you remote access the sql database?
• Do they offer dedicated app pools for DNN?
• FTP access?
• Bandwidth limit?
• Disk space limit?
• Plesk control panel and/or ability to do your own backups?
• Server specs?

I have been with PowerDNN for over two years with shared hosing accounts and a dedicated server.  I have never had a site go down or any issues what-so-ever.  Support is almost always within 10 or 15 minutes.  I'd prefer more disk space than what they currently offer but the trade off is you get super fast raid drives - which is one of the reasons my sites have never been down.  I've never had to worry about speed issues as my sites have always been fast.

Hope this helps

Greg