TiddlyWiki - Wiki in a single .html file that stores info into itself and runs on basically anything. It uses a very nice Web2.0'ish interface. I replaced my remaining text files with a TiddlyWiki today.
Worth mentioning twice, Freemind - Great mind-mapping software. I use it for keeping track of projects, classes, assignments, todos...
On the web
As for web resources, I'd say gmail got email just right. Used it for years and never felt like switching to anything else. I also use the google calendar, reader and of course blogger.
As for self-improvement I've been trying Joe's goals for a little while.