You know if you think about for every name brand program for windows there is a free alternative (I dare somebody to challenge with a windows program that doesn't have a free equivalent).
I have to give special recognition to the following programs that I use for web programming (some of which were already mentioned earlier in this thread):
Web Graphics: Gimp (alternative to photoshop)
FTP Client: Filezilla (alt to WS_FTP)
Databases: MySQL or Postgres (alt to SQL Server or Oracle)
Web Server: Apache (alt to IIS)
Server Scripting: PHP (alt over ASP)
Web Operating System: CentOS over Redhat Enterprise (when will Red Hat learn you can't charge money for free software...)
Besides free programs available there are also free codecs as well.
Ogg represents a free lossy alternative to MP3's, WMA's or AAC's.
Flacs represent a free lossless alternative to proprietary lossless standards such as Microsoft's WMA.
Theoria is a free video codec that is relatively new and has a lot of potential to compete with the name brand compression schemes.
Musikcube is a good audio player for playing opensource codes (and proprietary ones) and ExactAudioCopy is a great programming for ripping CD's into Flac's or Ogg's.