*Automated Backup system
This detail more then anything sold me on Dreamhost. 
http://wiki.dreamhost.com/index.php/Automated_domain_snapshots

*Detailed status site with catagorized RSS feeds!
http://www.dreamhoststatus.com/

*full shell
http://blog.dreamhosters.com/kbase/index.cgi?area=386

*LOTS of disk space / bandwith 
over 175G disk space/3 over 1.7TB monthly bandwith (disk/bandwith limits increase weekly) at the 7.95/month rate

*unlimited domains/subdomains hosted/forwarded/mirrored 

*very "liberal" apache config/feature set

*"installers" for popular web apps

*custom DNS

*Thier offical blog and newsletter are sometimes entertaining:
http://blog.dreamhost.com/
http://wiki.dreamhost.com/index.php/Category:Newsletter_Archive

*The unoffical dreamhost blog is also sometimes entertaining:
http://blog.dreamhosters.com/

*lots of helpful docs
http://wiki.dreamhost.com/index.php/Main_Page
http://discussion.dreamhost.com/

*ssh forwarding allowed