New Nirvana Box Set: don't get it. Just in case you were considering it. Just download the best tracks. The DVD sucks ass.
Green River is a pretty good band, though it's been years since I've heard them.
Treepeople, an earlier band Doug Martsch from Built to Spill, has some cool stuff. They aren't exactly comparable to other bands, but all those bands from that late 80s to mid 90s are pretty different anyway. I can only speak for the Treepeople records featuring Doug Martsch, however. Particularly Guilt Regret and Embarrassment. K Records released it a few years ago. I have an older release, on Toxic Shock(?) records out of Tucson that has 9 or so extra songs, including Handcuffs, one of the best rock songs of the 90s. Try to find that if you can, though I have no idea how hard it is to find now.
Other bands from the era I have enjoyed: Tad, The Melvins, and jesus, my brain can't remember anymore.
Oh yeah, speaking of jesus, don't forget the Jesus Lizard. While not really a part of that scene, they are my favorite hard rock band of all time (AC/DC, Bon Scott era, a distant second), and Liar is my favorite hard rock record of all time.
Karp is another fun band. Karp records are on K, and they have a good compilation on another label.
Go watch the movie Hype if you haven't already. It's really, really funny. And it has some cool music.
I think Chris Cornell and Layne Staley are two of the greatest rock vocalists of all time. I only mention that because I listened to Would off of Dirt and a few songs off of Badmotorfinger earlier tonight. Just great vocalists.