There are several threads already on this, but I personally do enjoy posting in them so here are my recommendations:
Opera: by far the most feature rich "out of the box" web browser. I prefer it to all others, but there is a bit of a learning curve. However, once you learn it and use the features I think there's no going back to other browsers.
Firefox: another great browser, I use it for sites that don't support Opera. It has an amazing list of cross platform compatible addons and has a few neat features I haven't been able to duplicate in Opera, like Tab Candy.
TextMate: a great text editor. It has a ridiculous amount of features for all sorts of programming languages, mark up languages, and general writing. It's fast and expandable.
Textual: a pretty IRC client.
Thunderbird: a functional replacement for Mail.app.
Cyberduck: an easy to use FTP client. I've heard good things about Fugu, too.
SYMBL: extends the power of Mac OS X with all sorts of great plugins. My favorite is Visor, it makes a terminal window drop down from the edge of your screen with a hotkey combo. It's really slick.
Spirited Away: a tiny menubar application that allows you to hide windows after a set amount of inactivity. It's great for small screens, or just to keep your desktop from getting cluttered.
I highly recommend picking a web browser besides Safari as it seems to hang constantly ( for short amounts of time, but it's still annoying) and really isn't anywhere near other browsers as far as features go. I personally don't like Chrome, and I don't like how ubiquitous it's becoming, but a lot of people seem to like it.