It's difficult to answer the OP when he says "roguelikes". I would say Diablo, but a lot of people say that's a Roguelike. It's hard because part of the definition of a Roguelike is procedural generation (as far as I know ... ).
But if we leave out ASCII games.
I'd say Diablo, a procedural randomized hack-n-slash. #1 has its charm but it desperately needs a run button. For that reason alone I would suggest Diablo 2. But #2 adds enough cool stuff that it's worth playing. If you plan on playing both, definitely play 1 first, otherwise you may never get through it for frustration at the slow pace.
Spelunky is a procedural randomized platformer, sort of an Indiana Jones game. It's also free. You will probably die several times in a row, often, so just sit back and try to learn something from each death. Even if that something is "I should maybe slow down a little" or "I got a bit cocky that time". It's fun.
I've heard that Noctis is a fun single-player space exploration sim. The content is procedural, but not random. That is, if you visit a given star and explore the first planet, another offline player will see the same things if he also explores that planet. The software is around 1mb, but the galaxy you can explore has about 78 billion stars. I think that's pretty outstanding, but I haven't played it yet.
Dark Cloud and DC2 are for PS2 I think. They're third-person RPGs with invention/crafting/townbuilding. Pretty fun.
There was an old old game (you will need DOSBOX) called Dungeon Hack that was sort of like Eye of the Beholder but procedurally and randomly generated the dungeon. You get one character instead of 4 plus 2 NPCs.