it's basically more morrowind. if you liked morrowind, you will also like tamriel rebuilt.
What other mods should I use?
What you should of course get is the Patch Project and the EXE optimiser. The official plug-ins by Bethesda are strictly optional.
I use BTB's edit of HotFusion's Economy Adjuster. It makes the prices of ingredients more sensible, increases the penalties for crimes massively, it makes sure that you don't get great weapons from Daedric creatures as easily, it makes merchants better at Mercantile, it makes training and fast travel MUCH more expensive, it disables bartering with Creeper and Mudcrab... I'm sure I've missed a couple of things. But this makes the game slightly more challenging. Although guild guides are still cheap as fuck.
I had BTB's version of Wakim's Service Requirements, which makes joining and advancing in factions more difficult, and makes a lot of faction members refuse you services unless you're of a high enough rank with them, or pay a surcharge every time. I turned it off because I found some things a bit too harsh and implausible. For instance, having to pay a 100g surcharge to be allowed to use the guild guide for 10g, while my interpretation was always that the guild guide was "public" transport. But you might as well use this mod, since you'll always have gold in MW, even with the aforementioned Economy Adjuster. And in the regular game, services are just too easy to come by. Surely there has to be a happy medium between that and the surcharge madness. Maybe make the surcharge one-time?
I already discussed LGNPC at length; you should decide for yourself if you want something like that. I can sympathise with people who say that MW is not really about NPCs and dialogue, and how it's actually pretty cool when you get some unique dialogue from a guy like Divayth Fyr. In the same vein as LGNPC, I've got Uvirith's Legacy and Rise of House Telvanni to add a bit to that experience. But I have not yet taken the time to play a Telvanni character with these mods yet, so I can't judge.
I haven't played Tamriel Rebuilt enough yet to judge it fully, but the parts that have been completed look pretty good to me. I do think they may have gone a bit over the top with the size of cities and the buildings in them compared to Vvardenfell, but of course Vvardenfell is supposed to be a bit of a shithole, so who knows. House Telvanni's massive capital city is pretty
. I like how they add their own things, without going nuts most of the time. For instance, there are many rivers in the area, so besides silt striders, you get transported by bugs that zoom through the water (well, you'll have to imagine the actual zooming!).
My computer isn't good enough for all those fancy graphics mods, but I do use stuff like Better Bodies, Better Heads, Better Clothes, Better Books, Weathered Signs, etc. These are strictly optional. If you don't mind the way these things look, or if you're worried that they might change the feel too much (some characters look totally different!), don't bother with them, because there are countless "Better [...]" mods, and before you know it you're slogging through them for hours, fixing every little thing. Weathered Signs is great though. It only makes sense that you can actually read signs from afar instead of having to walk up to them.
These are the main mods I use that I feel really modify the game. Everything else I've got are the tiny little things that you basically can't go wrong with: adding beds for rent in inns that didn't have them, being able to get yourself healed by Healer-class NPCs for a price (just because people keep telling me to "go find a healer"), flipping left gloves and pauldrons so I can tell them apart from the right ones, cutting back on "Excuse me, Nerevarine" greetings, cutting back on the "Solstheim" topic, getting rid of the message boxes when you create your character, Travelling Merchants to make the roads a bit more livelier, etc.
Basically all these little things that don't seem to do much on their own, but with make the game vastly more enjoyable simply as a combination, by fixing things that really only start bugging you when you've played for a while (e.g. every peasant in Vos knowing how to get to Solstheim). I got most of them from
this list way back in 2007 or so. Many of these mods are pretty old, but I still get my favourites from this list whenever I reinstall the game. The list is probably a bit outdated; I'm willing to bet that many of the fixes have already been taken care of by things like the Patch project.
Anyway, I think these are the mods that you should look into, and I do mean "look into" as opposed to "omg, you really NEED to get these now". Just check out the mods that add cool stuff, and leave all the gothic/vampire/S&M companion mods, all the dress-up mods, all the mods that add English-style pubs offering Guar Ale or whatever, all the "here is your own enormous mansion practically placed just outside of Balmora so you can play house" mods and all the other bullshit to the retards.
Maybe someone else can tell me if those mods that let you play Sixth House are any good. I briefly tried one of them ages ago, but I never really got into it. If they're good, I might try one again in the near future.