Aside from the graphics mods, I don't think you need much else, especially to begin with. There's nothing really essential, because everything's pretty well put together in the first place. I would've put over 1000 hours into that game, and tried out quite a few mods, but looking over them now, there's probably only half a dozen I'd bother to install again.What beginning mods would be reccomended without changing it to an entirely different game.
Here's what I'd be using:
- Unlimited carry weight, because I compulsively pick up every item I encounter
- Obscene amounts of money for my favourite trader, because I need to get rid of all this crap somehow...
- Join All Houses, to let you do all the quests for each of the rival factions
- A similar thing for the vampire missions (can't find it now, though...)
- The Morrowind Interactive Map, running in the background to keep track of where I've been
And once you've settled in to the game a bit, find yourself a house mod.
Aside from that, just take a browse of TESNexus and/or PlanetMorrowind looking for gameplay tweaks once you've got a bit of experience and see if anything strikes your fancy. Once you've seen everything the game has to offer, you might eventually want to go looking for extra content (items, enemies and quests), but that won't be for quite a while...