Alright, well I'm installing oblivion again, with FCOM too. I'm not gonna lie, I'm pretty excited to play. There remains one problem, the leveling. What's the best leveling mod for oblivion? I'm debating between nGCD and SPAM, and AF leveling. (If any of you guys have any more suggestions, post em here)

So can anyone tell me their past experiences with some of the leveling mods ya'll have tried out?

An nGCD/Progress combination.
Use it a while and you'll understand why.
http://www.gamesas.com/index.php?/topic/1095585-leveling-mods/
If you are a newbie to TES games, play with vanilla a little until you know what your looking for.

I use two character leveling mods. I choose which one I use based on the character I intend to play. I tend to use http://www.tesnexus.com/downloads/file.php?id=13879 when playing jack-of-all-trades characters and characters who change in some way during play. More and more I find I like to roleplay characters whose behavior is altered by their experiences in the game. Realistic Leveling, in my experience, adapts quickly to player/character decisions like this.

If I plan to play something like a 70's-era Dungeons and Dragons-style "class" I tend to use http://www.tesnexus.com/downloads/file.php?id=14065 NGCD, in my experience, functions best when players stick to defined classes and archetypes.

Whichever mod I end up using I always make sure to use tejon's http://www.tesnexus.com/downloads/file.php?id=14304 too. Progress allows the player to have complete control over how fast skills advance, and also provides a few new ways for skills to advance as well (missed spells can add a percentage to that skill's advancement).

All three mods are very configurable via the mod's .ini files.

I use nGCD. I like not having to rest or power level or anything, everything just levels naturally as I'm going about my business in the world. I tend to specialize, but I rank up minor abilities that are useful if the training is cheap.

Hehe, looks like Pseron's got a cut-and-paste answer to this question. So again, allow me to add a comment on "focused classes" vs. "just picking up skills" -- I'm naturally inclined toward the latter, and Oblivion's core mechanics strongly encourage this. Versatility is its own reward. The reason nGCD rewards specialization is to make it viable, so that the choice between spreading out and staying focused is a meaningful decision rather than a no-brainer in favor of picking up everything. And in the long run everyone still has the same skill and attribute caps regardless of how they got there; the extra benefits are for early specialization, and you don't ultimately lose anything if you choose diversity.

I love Oblivion XP since I find the normal "level up as you use a skill" to cause more problems than it's worth and XP worked wonderfully in Fallout 3, but that doesn't sound like what you're looking for.