For Marvel:

People give Liefeld a lot of (deserved) guff, but his early '90s stuff in New Mutants and X-Force were both pretty cool. Plus, it introduced Deadpool and Cable (before he got really lame).

I'm a big fan of the Hulk from that period, from the last days of the Grey Hulk, to the brief return of the Rampaging Hulk, to the combined Hulk, before the Onslaught story screwed everything up. Actually, as soon as he left the Pantheon, it all went downhill.

Most of the stuff that didn't involve clones and Peter Parker's parents worked well in the early to mid '90s Spider-Man.

The Infinity Squad was really cool when Jim Starlin was writing it.

There were a lot of good stories in Captain America. A lot of good interplay story-wise, so you felt like you were actually getting to know the heroes and the villains.

I liked the first 25 issues of Thunderbolts. A few of the few good things to come of the Onslaught crap.

Punisher and Punisher War Stories were dope, as long as they weren't perpetuating Republican propaganda. Thankfully that was only one issue.

And if Ghost Rider relaunched in the '90s, that was really cool for a while too.

For DC:

The "superteam" JLA was bad-ass.

I didn't read much DC back then, so my DC list is really short.