Probably FCOM, a lot of people use that. Also the Unofficial Oblivion Patch if you haven't got it already.

i already heard somewhere fcom... but i dont really know what is that, except it merge some mod.

And i also heard somewhere UFCOM... what is the difference??

Some of the quest mods I use are like...

The Lost Spires[Adds in another guild, lots of fun quests, and overall equipment for levels 10-15, with hard optional bosses, and good plot]

Heart of the Dead[A treasure hunt, with lots of puzzles, and the rewards aren't super powerful at all.]

Tears of the Fiend [Ever wonder why you're so godly without explaination? Why you do things others can't? Give this a spin. Some puzzles and some nice fights.]

Ruined-Tail's Tale [Really Good Companion Mod, but it requires a strong character to get through.]

Vilja [God, Ruin's got nothing on Vilja. She's the best companion I think you'll ever find! And you can start at ANY level]

Malevolent [You wear an enchanted piece of armor that can either aid you or hinder you on your choices. If you like story, go here. It's also a good start for evil characters. The Armor, can't come off until after the mod's done though, so that's a bit of a turn off.]

Dwemer Skyship [Easy optional quest, and a nice house mod, one of my favorites.]

Seaview Castle [Beautiful Castle, and funny quests. Become a lord of the castle! Ha.]

Midas Magic [ Again, requires a higher level character if you intend to get the more powerful spells. But still pretty fun, and the weaker spells are easy to get.]

Kvatch Rebuilt [Really Buggy, but you can rebuild Kvatch and maybe even become the Count! Get your own personal bodyguard, or fight in the new arena!]

The Underdark Saga with Viconia DeVir, and Stoker Wolff [HARD in my opinion, but it's totally worth it. Although the Underdark is kinda confusing when you first go in it.]

BladeSong [Needs a character higher then level 15 but still doable with lower levels, a quick and easy mod, with some great scripting and and even a war! You liked the Battle of Bruma? The war tops it completely.Plus a nice companion in the end.]

Frostcrag Reborn [Lots of mystery, and one of the longest dungeon crawls ever. Kinda overpowered rewards, but it's the dungeon crawls can take HOURS. I almost felt ill because of it once. XD.]

And Servant of the Dawn [might conflict with Battlehorn Castle or that may just be me. I absolutely love this mod...You can take over the freaking Empire with this, and take over another guild and go through a war as a general. Was extremely fun all the way through, and one of the oldest mods you'll find. As a sidenote, you join the Mythic Dawn. Although the reward can be a little overpowered, with infinite companions at your disposal, it's your choice to take advantage of it or not.]

If any of these interest you, just search the title up on Tes Nexus.

FCOM Combines some very massive mods together. This includes Francesco's, Warcry(i think thats the name...) Oscuro's and Martigen's.

the UFCOM I believe utilizes the new Martigen's since it uses a BSA file to store all the files.(much MUCH easier to uninstall this way)

Ok, here is the mod i will maybe use:

Lost Spire
Artifacts
Armamentarium Complete
A mod to change my map... from the list in my signature
Frostcrag Reborn
Map Marker overhaul
Midas Magic (maybe, not sure, can unbalance the game, i dont want to have a "super rainbow attack, one shot kill spell")
Imperial Furniture (maybe, i heard some bug in the comment section)
Harvest [Flora]
http://img85.imageshack.us/img85/9236/drevil.jpg

Trust me, mods will change your oblivion experience completely, and make it extremely fun. There's something out there for everyone! But if you have any items in Frostcrag, take them out before you start Frostcrag Reborn. And you'll have to rebuy the furniture. Also the dungeon crawl will be extremely long, with many enemies, so before you start your adventure into the second quest [After you kill a certain lich...] get alot of supplies. ALOT.

i am a mage, so i use restore health and sleep for magicka... or i wait until it completely restore... normally, after 1 min, i should be ok... night eye for torch, and conjuration... and maybe bound armor, so no repair hammer, so what supply i should get??

Some Enchanted Equipment, and some good weapons. You might want to bring along Azura's star to recharge your weapons if you can use soul trap and have some black soul gems. Although the mod does provide plenty of good weapons as you progress [Alot of staves early on, and a few later, and a couple of swords near the end]. And when you finally download it, you go inside the data file, copy everything in there that has names like: Music, Textures, Meshes, Distant LOD, Sound, etc.[Not things that can be opened with notepad or word. Those are either a read-me, or a walkthrough.] and go to your oblivion folder and paste everything in the Oblivion Data folder, and enable it when you start the game with the disc and go to data files, check it on, and start playing! If you don't get it, you can try looking up a tutorial on youtube. It's really easy.

And besides the first quest, it's not really dark. A few more tips for Midas Magic, and Lost Spires.
Midas Magic: Buy the new books from Midas in the Arcane University and read them. You need to gather ingrediants, put them in the black container, and cast a spell, and eat the new item created to get the spell. Downstairs in the shop there's a portal to the Astral Realm, and you'll need to use the new Force spells to get to a small island, and from there finish the quest. Then you can open up even more realms and gain the more powerful spells!

Lost Spires: In three of the spires, there are portals. In each of these portals you can find a boss, and a chest containing some magical artifacts. Only one time will entry be necessary to proceed in the quest. So if the find the first time hard, you can decide to skip the next two. And some of the rewards might be considered powerful but for the level needed to proceed, it's good. Some examples of the rewards are...A feather that gives you the ability to carry 150 more pounds of items, a food that when eaten will grant 50% resistance to fire, and 3 reflect damage forever [I think], and a coin that increases your luck by twenty. Although alot of rewards are only useful for asthetic purposes.

ok i will not use map marker overhaul, since it use OBSE...

i dont think i can trust OBSE...

OBSE is required for alot of the best mods. Oblivion Script Extender never really bothered me. Just took the data needed, put it in my oblivion folder, and click bose when ever I want to play.

but can OBSE modify some thing in my game... like my save file, and become corrupted if played with no obse after??

OBSE is totally safe

You can switch back a forth, but I'd suggest only playing obse. I mean, it's oblivion that makes any mods you download even better! Some of the best mods even require it!

Ok, here is the mod i will maybe use:

Lost Spire
Artifacts
Armamentarium Complete
A mod to change my map... from the list in my signature
Frostcrag Reborn
Map Marker overhaul
Midas Magic (maybe, not sure, can unbalance the game, i dont want to have a "super rainbow attack, one shot kill spell")
Imperial Furniture (maybe, i heard some bug in the comment section)
Harvest [Flora]
http://img85.imageshack.us/img85/9236/drevil.jpg
Reznod Mannequins http://www.tesnexus.com/downloads/file.php?id=2055
Dude Wheres My Horse FINAL http://www.tesnexus.com/downloads/file.php?id=3861
Cyrodiil Transportation Network http://www.tesnexus.com/downloads/file.php?id=4520
Auto Book Placer http://www.tesnexus.com/downloads/file.php?id=10561
wz_Inventory http://www.tesnexus.com/downloads/file.php?id=3595