I've been playin around with Gallery2
http://gallery.sourceforge.net/ but I will admit it's performance could be improved... I've removed things I'm not gonna use like the rating system. It does and behaves how I like so far. There looks to be a lightbox module that's possible to use..but I'm not sure of the ease of installation. I will admit that it would be nice to just click on the thumbnail, overlay the 640x480 image, and remain on the thumbnail page with the option to click another link to see the full image description and so on.
Zenphoto doesn't seem to deal with EXiF information yet otherwise I'd try that.
Hmmm.. think I will attempt to get lightbox working on my gallery.
I do like the Gallery Remote application.. it runs on the PC and you connect to your gallery with it.. then you can just drag and drop images into whatever album and click upload.
Once I've gotten everything how I like then I'll try something else to see if it's better for what I want and its performance.