This page contains various links I find useful when playing Morrowind.
In my opinion, the Morrowind section of the UESP wiki is the best game information resource for Morrowind. It lists everything you could ever want to know about the vanilla game. I would even sing praises if I could carry a tune.
The official Bethesda Softworks Morrowind forums are very helpful. The people are nice and willing to discuss any Morrowind idea, problem or question you might have and even the childish Fargoth bashing seems to have died down. And if you're lucky, you just might get a fishy stick.
I also visit the UESP Morrowind forum.
Google has quite an exhaustive list of Morrowind mods. There really is a lot to choose from and with different people having different tastes, you should check the ones that appeal to you for yourself.
Personally, I cannot play the game without the following mods:
- Bethesda's official plug-ins: since they're official, I consider them to be a necessary part of the original game.
- The Morrowind Code Patch: fixes a lot of the game's code-based bugs and introduces some sensible enhancements.
- The Morrowind Patch Project: this one also provides all sorts of bug fixes for the game (but construction-set-based) and that's always good.