If you're on a Mac, I can't recommend TextMate enough.

I really like Textpad on Windoze. It is shareware and you can download an full copy from: textpad.com

I like BBedit. A lot of designers swear by it for HTML and CSS hand coding, but most of the features are actually for developers and programmers. It supports PHP, Java, Perl, Javascript, XML/XSLT, C++, Python, Ruby, etc. Apple says:

An intelligent interface provides easy access to BBEdit’s best-of-class features including grep pattern matching, search and replace across multiple files, function navigation and syntax coloring for numerous source code languages, FTP and SFTP open and save, AppleScript, Perl, and Mac OS X UNIX scripting support, glossary support, and a complete set of HTML tools.

For HTML/CSS, some of us have been trying out Coda and it's pretty awesome.

also try coda...really great app for mac. i like more than anything else. they have a cool site too.

Coda or TextMate - they're both fantastic. The latest version of TextMate has Subversion support built into it. Personally I do all of my coding in TextMate on a Mac.

It's old-school, but I do like VIM. :-)

Lance Parsons --- UTO asu.edu

I would say Ultra Edit!  We have a key for it as well.