Camino (Gecko-based browser) - Also use Safari, but am partial to Camino as my main browser.
TextWrangler (text editor) - Does it for all my coding needs; good interface, fast multi-file find and replace, built-in grep, syntax coding for a bunch of languages, and it's free.
CSSEdit (CSS editor/live preview) - Only started using it last week when I got it as part of that MacHeist bundle, but WOW is this a time saver--it's already saved me several hours of work and frustration, and it's oh-so-pretty to boot. Can't believe I wasn't using it before.
Interarchy (FTP and more) - Longtime user, but its best features are lightning fast mirroring of only changed files (can compare 2700 files for changes in under 10 seconds), and you can live edit a file on the server (upload automatically on every save) in TextWrangler via a right-click option.
iMovie HD (NOT 08) - All that and a bag of chips.
iPhoto
And, when I'm doing anything with newsgroups, Thoth (awesome in many ways for binary-centric newsgroups, but sadly no longer sold--holding onto my license as long as it will run).