I recently started a very roleplayed playthrough of oblivion, I am fairly new to oblivion modding and am not familiar with a lot of things. I am wondering if there are any mods that I should try out (not overhauls, I will attempt to try OOO next time I play, for some reason this time it made the guards floating heads with bows under them) I would also like to know about other sites because the only one I know of currently is Nexus. I've just assumed that like Morrowind, we lost a crap ton of mods with the PES indecent.

What do you want to change about your game? Tell what some of the things you would like to change and we may be able to suggest some mods that will do those things.

Nexus is where I get most of my mods. The only other site I use with any regularity is http://www.tesalliance.org/index.php/

I would like to make it more difficult, I would also like to make it more unique or bizarre like morrowind was.

Here's a few mods you might want to take a look at. You mentioned that you don't want overhauls and, though these are large mods, I'd say none of them are truly "overhaul" mods.

http://www.gamesas.com/topic/1506000-relz-the-unique-landscapes-project/ These mods go a long way towards making Cyrodiil a visually more varied and interesting place to visit. It still looks like Cyrodiil though, so don't expect Morrowind-level strangeness even with these mods installed.

http://www.gamesas.com/topic/1515287-relz-better-cities-thread-52/ Again, this won't make cities are unique or individualized as towns were in Morrowind, but it's a vast improvement over vanilla cities, in my opinion. You can choose from several options, including the option to make towns open, as they were in Morrowind.

http://tesalliance.org/forums/index.php?/files/file/1318-wac-waalx-animals-creatures/ This adds a boatload of new creatures, new armors and new weapons and a few new places to visit around the game world. Some of the creatures are a little strange, so if you like Morrowind's creatures this may be a mod to check out. I like the mod mainly because of its armor and weapons though. It adds some of my favorite robes and staffs.

http://tesalliance.org/forums/index.php?/files/file/1283-martigens-monster-mod/ This is a classic creature-adding/difficulty mod. It doesn't just add new and stronger creatures, it also completely revamps creature behavior. The world is much more random, spontaneous and surprising with this mod installed. You'll never know what's going to happen next, or who it will happen to.

You'll have to register at TES Alliance if you want to download Waalx or Martigen, but it's well worth it.

although it's an overhaul, you may want to check out Maskar's Oblivion Overhaul. Its really easy to install (only one esp file and no patches are ever needed), and it is compatible with everything without needing patches.

Maskars adds a ton of unique creatures and items to the game, making it feel more unique and it makes the game harder. How much harder is up to you, since you can easily edit the difficulty in the Maskar's ini file.

Do I have to start a new character for it?

No. You can add it and remove mid game it with no problem (I'd probably console to the testing hall and do a clean save if uninstalling mid game). It comes with a large textures and meshes folder but it does not replace any files so uninstalling is easy.

It looks like Maskar is in the process of uploading a new version. So you may have to wait until it gets uploaded in order to download it. http://www.nexusmods.com/oblivion/mods/42780/? Might be a few hours. Also, it requires OBSE 21, but so do a great many other Oblivion mods.

I'm pretty sure I'm using OBSE