The newness of my MacBook is decreasing rapidly. I’ve installed GIMP (works nice and zippy), GraphicConverter (useful for quick resizing of images), TextWrangler (an editor), MS Office 2004 (although I’m considering to install NeoOffice and use MS Office via Parallels only).
I had a look at the websites of Scribus and Inkscape, but I think I’ll wait before installing them.
I’ve installed the Subversion command line client and a little plugin (aargh, can’t remember the name) that allows you to upload and commit files from the finder. I didn’t like SvnX much.
I like the size of my MacBook. Much easier to lug around. Quicksilver is very useful.
(update) The SVN plugin is called SCPlugin.
You should install MacPorts as well as a GUI for MacPorts called Porticus. The combination really brings in the true power of Linux to your Mac.