Let's see here...
Overhauls: none. Overhauls have never appealed to me, for some reason. Possibly because they're such large mods which change so much (obviously the point of an overhaul!)--but I'm a bit of a control freak when it comes to mods, and prefer more specialized control. I may one day try a game with OOO, just to say I've tried it, but it's not high on my list of priorities.
Texture packs: again, the control freak in me rears her head.
The only large-scale texture pack I use is Bomret's SI. Other than it's all smaller packs (for vegetation, Ayleid ruins, lava, etc.). I like to pick and choose; what can I say. (I do the same with Morrowind, typically installing a major overhaul like the Visual Pack first as a base, then rampantly overwriting it with individual retextures.)
City replacements: other. Bravil Blood & Mud and http://tesnexus.com/downloads/file.php?id=19589. Blood & Mud is interesting. As a city expansion it's pretty good, but not so much as a quest mod. (Mostly because I'm having trouble hearing the voice actors, even with headphones and the volume cranked up, and frankly the English translation is terrible.) I absolutely love ImpeREAL City, though. It's become a staple in my game already.
Realism mods: Real Thirst & Hunger (Cobl editions) and Real Sleep Extended. I also voted for other, since I use a few other mods I consider "realism" mods, if only for what they add to immersion and role-playing: Enhanced Economy, Cava Obscura, Curseman's Anti-Extinction Mod, Dungeon Actors Have Torches, Real Lights (from All Natural), Enhanced Weather.
Leveling mods: nGCD for me. Still using an older version due to laziness in regards to upgrading to v2.