SK or Rogue?

[JurisDictum]

Rogues cannot solo for the most part. You can inefficiently solo as a twinked rogue at lower levels, but pretty soon you'll need someone to tank or fear for you. The other downside is some people find them boring, because you spend most your playtime backstabbing and pressing your feint macro.

Other than that, they are a great class that is overall the best dps in game, not overwhelmingly expensive to gear, and has an easy time walking through dangerous zones.

Shadowknights are arguably the best group tank in the game (although I think the perfect group uses Paladin), and are solo-capable. However, they are expensive, slow to level, and probably the worst raid class in classic EQ. They occupy a werid space where they take a great deal of platinum to twink, but really aren't a good endgame class*. But if you really like tanking groups, it might be the class for you.

*Geared Shadowknights are really good at PvP, so on red they are a good endgame class. But there are always too damn many of them, and it tends to annoy the very raid guilds you want to join for high end gear.