Because I have been happy with Firefox, I have not checked out (extensively) many of the other browsers that are out there. The other day, however, I finally removed IE 6 from my computer - completely forgetting that this is the browser my mom uses when she comes over to play on the computer. Firefox, with the zillion tabs that I have set to open automatically, proved to be a little "much" for her (and she kept closing out all my tabs by accident), so I looked around for an alternative (since I simply refuse to load IE 7 on my machine).
I decided to try FlashPeak's Slim Browser, and it's proven to be a perfect browser for Mom, and my computer. It's light, has tabs (if you want them), skins, pop-up killer, search, etc., etc. Did I mention that it's light? It's not a resource hog, and I think it would make a great alternative browser on library machines that are getting old or are simply a little light on RAM. I love Firefox, but it's a killer on old or slow machines. You may also be able to get Slim Browser on Gates library computers - and, according to my IT person, it's a bitch, if not impossible, to get Firefox to run on a Gates machine (go figure) (and, funny, but IE7 is also not fully functional on our Gates computers).
It's a Windows app, so I'll be bummed to lose it when I finally jump to Linux on the desktop. But for now, it's doing a great job for Mom.