http://www.spiderwebsoftware.com/They've got a Humble Weekly Bundle this week, with the vast majority of their catalog from their twenty years of operation involved in it.
So yeah, you should possibly consider getting on that shit. If you're at all into this sort of gameplay, I'm going to say it's almost assuredly worth your money. Jeff Vogel and his little crew (which consists mostly of him) generally put together a fun, well fleshed-out romp. And I take more pleasure than I should in revisiting areas from older games in newer ones to see how they changed.
Now there are some valid gripes to make here. Sometimes the games aren't as well-balanced as they could be, sometimes the turn-based combat can get a little fidgety to manage, and the games themselves can look samey. Also remakes, remakes as far as the eye can see! First there were Exiles 1-3(.5), then they were remade as Avernum, and now he actually has a remake of Avernum (titled, awkwardly enough, Avernum: Escape From the Pit). And the Nethergate game in that list is a remake itself.
Anyway, the few times they make a new engine, they tend to port some of their older stuff into it.
Still, it's hard to beat for the hours and hours of murder-hobo 'swipe everything not nailed down' style of fun. Oh and for those that remember, their Geneforge setting is the one we tooled around in for Unicorn's Mafia game.
Much thanks to LTK for bringing this to my attention.