Wow. I've used dreamhost for over 2 years and had small issues that were fixed. Had 99.7% uptime. I've never tried hostgator, but i'd still prefer dreamhost though.
I have used both, I will prefer hostgator over Dreamhost, But will prefer if you are willing to start from very small budget !
Hostgator is much better than Dreamhost. Plus, at HG, you get CPanel...whereas, the DH have a crappy custom control panel.