[unsignedqword]

Some (maybe) lesser known gems for Windows machines:

http://www.peazip.org/ - Zipping/Unzipping utility, better than WinRAR or 7-Zip

http://implbits.com/products/hashtab/ - Shell extension that adds a panel in the file properties window that can compute and compare a hash against many different hash functions

http://mactype.net/ - Shell extension that gives various options to modify Windows' anti-aliasing scheme. Useful if you're not a fan of TrueType's look. Can cause noticeable lag and drawing issues on some less powerful systems, though

http://cmder.net/ - Alternative, more-featured terminal emulator for windows (works with both Cmd/PowerShell)