Genesis help

Well, you've named the big four, the ones by the "classic" five-piece lineup, so it can be tough to know where to go next, and none of it will really sound the same. Fortunately, in the case of Genesis, things evolved in a rather linear way. Trespass is also very good, and is considered the first "real Genesis album" by many, because it really developed the signature interplay between the keyboards and acoustic guitars. It was the one right before Phil Collins and Steve Hackett joined, but the style established by Anthony Phillips on guitars was pretty much what you hear later with Hackett, and the percussionist in the band wasn't really set anyways.

After the "main sequence", the two 1976 albums with Hackett but without Gabriel were still more prog than pop. This is actually my favorite version of the band, as it's where I started with them. The live album by that lineup, Seconds Out, is still my favorite Genesis live album.

But all of those were already mentioned by others. What you need to know is that once they went three-piece, the prog gradually eroded, giving way to pop, but there are great prog nuggets on each album, all the way to the end. ...and then there were three... is derided by a lot of Genesis fans, but I happen to like it. There are three or four songs with some nice extended instrumental breaks. Duke features the terrific six-song "Duke Suite", but it's spread out over the course of the album. The first three parts open the album, the last two close it, and "Turn It On Again" (you've probably heard of that song, eh?) is actually featured as a reprise of sorts in the middle. The remaining six songs are pretty much pop, but a few of them get a little adventurous. Duke is generally considered more prog than ...and then there were three...

If you really strongly prefer the prog over the pop, you pretty much have to pick and choose songs from the remaining albums. I could give you a list (sadly, there aren't that many), but will hold off on that for now.