As the topic title suggests, I am looking for the best leveling mod there is. Or at least one that is rather lightweight. Would love if I could continue my character with it as well.

first, you've got to scrub all the floors in mournhold.

what are you looking for in a leveling mod? there are many available that tackle leveling up in many different ways.

are you looking for something to slow down how fast you level? something to make leveling seemless?

The most popular levelling mod, by far, is Galsiah's Character Development (GCD). Your skill increases cause attribute increases as they happen. You learn by doing (or by paid training), and there's no need for a level-up screen or tracking those miserable "multipliers". It's got a lot more interactivity between skills and attributes, and a skill typically has smaller effects on several other attributes besides the primary, which means that you do get some improvements in attributes which you don't increase through their typical associated skills. Skills and attributes over 100 are integrated seamlessly, and work extremely well. It also adds magicka regeneration on-the-fly (a bit fast for my liking; I modded the rate down to about 1/4), so your spellcasting character doesn't spend half his or her life resting. The rate of hitpoint increase is marginally to drastically lower than "vanilla", depending on the character (you only get hitpoints by raising Endurance, not at each level increase), so it's a difficulty enhancer whether it claims ot be or not. Overall, I consider it to the be best levelling mod out there for pure thieves or mages, but pure fighters or fighter hybrids may find the lack of hitpoints debilitating as the game goes on, especially against higher-level mod-added MCA or Creatures opponents.

MADD Leveler uses a similar system in some respects, but is not as "drastic" a change from the "vanilla" scheme. While the majority of your attribute increases happen as your skills improve, it retains the level-up screen, and allows you to manually select 3 attributes to increase by a single point each. That gives you a little bit of conscious choice about how to shape your charater, while not having total control, which I find to be a good compromise. Skills and attributes over 100 are handled by long-term fortifications, which is a bit clunkier than the elegant system in GCD, but still very functional. It doesn't have a magicka regen function (I use a slightly "toned down" version of Fair Magica Regen" with it), and the only real "negative" I've encountered is that it seems to slightly speed up the rate of levelling. I much prefer this mod for fighter and fighter-hybrid characters; otherwise I go with GCD.

I haven't tried any of the newer levelling mods, so I can't comment on them.

I like GCD but its in no way "lightweight" as you put it since it completely changes the leveling up. It forces you to become more of a "pure" class or at least focus in fewer skills. Also it eliminates the leveling up process. Levels only exist in the backround (there is no lvl up screen) for the games lvled lists. As I said GCD is very game altering. You can't end up as an overpowered god, a master warrior, thief and mage like you usually do. Also you can't end up as master of all three guilds. 1 or 2 at most. For GCD it is recommended but not required that you start a new game.
GCD is awesome. It makes the game harder and it makes the skills your choices in the beginning matter. It just makes the game more sensible. If you are a mage for example you end up with a larger mana pool, magicka regeneration but you are quite a weakling with low endurance. I'm playing a mage/thief hybrid and i'm lvl 20something and i got like 60something hp. If i was playing normal morrowind I'd be god by now. Unkillable with hundreds of hp, and a powerful mage with heavy armor and a huge weapon. Now with GCD if I see a daedra I have to use tactics to kill it or I'm dead in one hit. On the other hand I have like 400+ magicka so thats nice Also you are not doomed to be a weakling forever. Because hp increases with skills too not only with endurance. So if you invest in skills like acrobatics or armorer or armor skills etc. your hp increases. I'm just putting it off cause i got no cash atm

The other big lvling mod is Madd leveler. It is a lot less invasive than GCD and merely alters the way you lvl up by removing the multipliers in the lvl up screen. In this way you don't have to grind your skills and perfectly plan your character so you get that precious x5 multiplier. You also gain +1 in an attribute for every 3 skill increases so you can still end up as an overpowered god if you want to. Its also a very easily customizable mod so you can tweak it like you want i.e. make atribute progression slower. Works best if combined with a mod like Talrivian's hp so you don't have to grind endurance skills in the beginning and a magicka regen mod.

It is a very good mod but still i prefer GCD.

There's also a few more lvling mods. Here is a great guide that can help you chose http://www.mwmythicmods.com/Gluby/Gluby_CharacterDevelopment_Mods.htm. Its awesome and has sections for other stuff too.

Well when I say Lightweight I really meant A small filesize.
But GCD sounds like exactly what I wanted.
EDIT: Anyone have a mirror the PES link won't let me download, when I click the file to download it says something about an invalid header.

Alternate Levelling by Balor might be worth a look. It nerfs the level-up benefits and adjusts character skills and abilities on the fly based on use. And I'm pretty sure it's compatible with just about any Magicka Regen & Dynamic Ability-Based HP mods you want to use.

Size-wise it's about 1/10th of a MB.

Well after mroe reading Madd seems less restricting, so I think I'm gonna go with it, but I still need a mirror, PES is still giving me an invalid Header when I try to download anything.

You might want to try again. I just grabbed it with no trouble.

If it still won't work, I could probably send it to you. Just PM me with your e-mail.




KF

I like http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=7429

Use GCD and you'll never want something else




probably

Alright I got past the Invalid Header gonna try GCD, since I just now realized that nGCD was only made because of how good this one was. Mods can lock.