Textmate of course. After that I'd get MacFUSE from Google Code for connection to Unix boxes, CheckOff for simple task lists, Twitterrific, xPad for notes, pgA

Textmate of course. After that I'd get MacFUSE from Google Code for connection to Unix boxes, CheckOff for simple task lists, Twitterrific, xPad for notes, pgAdmin3 for PostgreSQL, Mailplane for GMail accounts, iWork08 or NeoOffice for Office apps, Parallels for virtual machines, and Adium for chatting. You're all set then!