Camino, the best Gecko-based browser NOT named Firefox 3, has just been updated to version 1.6.3. This update, which seems to have rolled in 1.6.2 along with it (at least I never got the 1.6.2 notification, and I use Camino pretty frequently), sports the latest update to the Gecko 1.8.1 branch, including several critical stability and security fixes with better ad-blocking. Plus, it no longer crashes if a pop-up is displayed while dragging a bookmark.
Even though Firefox 3 is now a largely native Cocoa application, I still appreciate Camino's interface and speed. If nothing else, it's great to use as a Firefox 2/Gecko 1.8.1 testing agent when developing websites for compatibility.
You can download Camino here; optimized builds aren't available as of this writing, but check this site over the next few days for updates.