I've been playing Oblivion on and off and am getting close to finishing the Main Quest. This has been my Vanilla run and I feel I've got a good idea of how the game works and what doesn't work for me. So I'm looking at mods and mod utilities and mod advice. Here is the list of mods I'm thinking of using after a bit a research:

Realistic Leveling
Elys Uncapper
Legendary Abilities
OOO+MMM/FCOM (Convergence)
Grandmaster of Alchemy
Alchemical Formulas
Persuasion Overhaul
Sigil Stones Expanded & Extended
Sigil Stone Selector
SM Encumbrance and Fatigue
SM Combat Regen
SM Hand Combat V1.0
Appler'sPassiveBsigns (Looks interesting, not sure if I really want it)

For utilities I'm quite sure I need OBMM, but I'm not sure I understand what BOSS and Bash are supposed to do. So I'm looking for some input from you smart people about what utilities I really need and if there are any big mod conflicts that I should know about.

BOSS orders the load order correctly. Load order determines what overwrites what.

Wrye Bash does many many things... the bashed patch in particular allows you to merge certain aspects of different mods so that they DON'T just overwrite everything that conflicts between them... needed for stuff like FCOM

As for recommendations:
http://www.gamesas.com/index.php?/topic/1072579-the-any-mods-list-of-topics/page__p__15593408__fromsearch__1&#entry15593408... or just browse through those topics.

Bash. It's not a question of what does it do, but more of a question of what doesn't it do. It won't make you tea, for one, and it's installer doesn't work with scripted installs(like OBMM can do), but short of interact with the real world, it can do pretty much anything you need. It has a ton of features that'll make your day much easier. Using FCOM? Bashed Patches can help. Twenty characters with different load orders? Character Profiles really help here.
Want to know what each and every effect added by a alchemical item is, and have mods adding more then 0 new ingredients? With a little help from his friend COBL(Common OBLivion), you can do that and more.
Need to save on load order slots? Check if your mods can be merged, then do so with a Bashed Patch.

Wrye Bash really does more then OBMM, and most of it it does better! The common statement on Wrye Bash is that it has so many features, that it makes http://www.vagabondish.com/wp-content/uploads/2007/04/wenger-85-swiss-army-knife.jpg look like a kids toy. But don't let that scare you, most of the features you might never need. Most of us players won't need to use Morph Factions, nor will we open the Power Exhaustion part of the patch, for example. But the fact that it can launch many useful programs(assuming you have them installed) is a godsend, but for modders who do more then just CS work, you might want to check out http://www.invision.tesalliance.org/forums/index.php?/topic/1757-relz-insanitys-oblivion-launcher/, which is great for some people.

Mind you, I wouldn't recommend jumping right into a full FCOM install if you're new to mods. It can really hurt some peoples sanity if they fail to read the instructions, I hear.
And while it is said to be one of the best set ups out there, it is also a massive headache sometimes. And often way harder then vanilla. Like, harder then vanilla with the difficulty slider all the way to the right, facing a massive mob of daedra while standing in lava, and you have no weapons or armor, and you're silenced. With 5 unarmed skill.

I am working on a walk-through for BAIN (Wrye Bash's installer) installation of FCOM and non-FCOM setups. At the bottom of the http://sites.google.com/site/oblivionpoinfo/walkthroughs/bain-installation-of-modded-oblivion is a link to a thread in which I helped someone install OOO+MMM. You should be able to learn how to install your other mods (except for FCOM) through it as well, or reference the guide.

Thanks for the feedback, I now have a few more mods to look at. I'm familiar with modding for Morrowind and Fallout 3, so FCOM doesn't sound too scary.

It looks like I've got some downloading to do, now I wish that Bash could make tea!

Good to know. I am almost done with the BAIN guide for FCOM installation, actually. I just downloaded all of the requirements for the basic FCOM setup and am in the process of writing up converting them to BAIN packages. You can see what is left by checking out the "In-depth BAIN Guide" link in my thread. I will focus on the FCOM-specific portions for now, so it is not as bad (looong) as it looks, haha.

Thank you all for your input, I spent a few hours downloading (my mod count somehow ballooned to just under 90 :hubbahubba: ) and I went to work installing. I think all the terror about installing FCOM prepared me well, I found it incredibly easy and straight forward, I may tweak my load order a bit but my test playing yielded no problems at all.