http://www.eapps.com/
Interesting web hosting company. VPS based hosting from $10/month including a dedicated IP and mailserver with webmail (squirrelmail / OpenWebMail).
http://www.mediatemple.net/
A hosting provider recommended by Happy Cogs (who designed the WordPress 2.5 admin panel). $20/month for shared hosting (1000 domains, 100Gb, 1Tb) , $50-$150/mth for virtual, $750/mth for a balls out dedicated server. Looks *very* good.
http://www.webhostingpad.com/
As at Mar 2008 you get 1.7Tb of disk and 17Tb of data for $9 a month (6 month contract). Useful for backup and media, etc. Probably too cheap to be reliable.