We still play 1st ed rules; we've been playing since the box sets, and see no reason to change. And Gamma world, for the Tech stuff. (White Plume Mountain was first, iirc)
We have modified some things over the years as too powerful. :)
Our last gig had our Gang on my world's version of a space shuttle, when Vecna found them.
Someone made an incredible roll; and they instead of being; oh whatever Vecna would do to you for totally killing all his enemies, and destroying his skull citadel, with said peeps inside, they ended up in the Deity Witness Relocation Program, as Drow Elves, chained to a wall upside down. Naked.
They're in Strad's basement, just now. :)
At our age, we only play a game every few years, but they're good. :D