I must give thanks to Alex rabe for all the work he has put into his Gallery Plugin. I use it on most of my blogs and find it very easy to get up and running quickly. There are some limitations that I think are beginning to be addressed like the SEO aspect and adding some functionality for more than just a gallery, but an online inventory like CMS or a Zen/Uber/WP cart site without all the horrendous messing around with the first 2 anyways..
I will carry this post on over the day as I check out the new features of Nextgen gallery..