I had an awful experience with HostGator recently when I got my 1st dedicated. Switched to SoftLayer and I'm very happy. I have 2 DreamHost accounts and I like them very much for certain things. Their MySQL performance is horrid though so I wouldn't say they're good for WordPress unless you're not concerned about snappiness. I keep hearing good things about
Slicehost - VPS Hosting.
Oh and if you're concerned about switching hosts (you should be) go with someone who uses cPanel (that'd be HostGator, NOT DreamHost) which makes moving hosts a BREEZE.