LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
TortoiseSVN - The coolest interface to (Sub)version control
SmallDevTools - Handy developer tools with a delightful interface
SnailSVN - Similar to Tortoise SVN for Windows but integrated into Finder
Profitable developer tools database - A database of 103+ hand-curated profitable developer tools
Xversion - Super easy enterprise class version control.