Voted BAIN. OBMM may be easier for mod installation, but if you ever want to remove one, you'll wish you'd used BAIN.

wyre bash BAIN FTW!

OBMM - I use a .txt document where I write down the order in which I've installed my mods. This solves the question of "which file takes precedence" and I much prefer this to learning Wrye Bash which is way too complicated for me.

That may work well for a small group of mods, but if you are serious about modded Oblivion you need to learn to use your BAIN.
Naturally I voted for BAIN.

That Fallout Manager sounds nifty, though. Since the games are som similar it should be easy to convert to Oblivion, I think.

There is http://www.tesnexus.com/downloads/file.php?id=32277

It does add a few more features to OBMM, but no it is not FOMM by any means.

FOMM - favorite feature is that you can highlight a chunk of mods and then drag and drop and when you reach the top or bottom it scrolls the pane for you. It can also let you choose per each and every replacer file (that means each texture, each mesh, etc) which mod wins - which is more advance than BAIN.

I still prefer the visual entire mod at once version of BAIN though and have rarely seen where being able to have that feature is all that desirable. What a headache to keep up with.

I install 95% of my mods manually. I use OBMM for mods with installation scripts (such as Enhanced Economy) that provide configuration options.