F-Spot
I messed with F-Spot today. Or rather, from about 1:30 to 2:30 this morning. For those too lazy to follow the link, F-Spot is a photo manager, much like Picasa or that iPhoto garbage. Anyway, you can sort, view, crop, enhance and tag the living daylights out of your photo collection with it.
I really like the interface, it's very intuitive and much like Picasa (or vice versa, I dunno which came first). The tags and filtering are great, and provide nice visual cues for your sorting. There are also numerous editing tools and they seem to work at very respectable speeds, and lossless no less.
My problem is that my pictures are a real mess of folders, and very few are tagged with the correct date and time in the EXIF info. It looks like I'm going to have to go through adding a folder at a time and weeding out dupes and stuff. That might take a while, but I think it will be absolutely worth it. I'm gonna get some sleep now.
Update (11/11/2006)
I went through and added 2878 photos from 2001 - 2006, all the pics I had. I've got 20+ different tags. Crazy, it took a while but I think it'll be worth it if I keep maintaining it with new pictures. Rad.