I've been looking around on TES Nexus to see which magic mods (either overhauls, or less) seem to be the most up-to-date and popular. I'm not seeing anything that clearly stands out.

The thing I'd like to find most of all is a mod that allows for:

1. Hiding 'obsolete' or 'semi-obsolete' spells, or otherwise allows separate display sets of spells

I'm going to try this Midas Magic Spell Sorter mod and see if that does what I'm looking for:
http://oblivion.nexusmods.com/mods/40943

"Less Annoying Magic" used to be popular from what I understand but I can't find it.

"Midas Magic" also used to be popular but I'm a bit leery of that mod making things a bit unbalanced?

I'm not necessarily looking for a huge magic overhaul that adds hundreds or even _any_ spells, but just interested if there are good up-to-date magic mods that guys recommend.

LAME is still popular, is balanced, and works well with other mods. You can find it here: http://theelderscrolls.info/?go=dlfile&fileid=219

I use LAME personally, as well as Soulgem Magic: http://oblivion.nexusmods.com/mods/35393

Midas adds a lot of big spells, but I don't personally think it's balanced as some of them are overpowering. Some of the spell effects are rather spectacular (look on Youtube for examples) - like nuclear blasts. A lot of people love it, but if you want something more low key than LAME is probably more up your alley. LAME also organizes and sorts spells by school.

Cool! Thanks Stromgarde

I use Supreme Magica and LAME together, seems to work out quite well.

What does Supreme do in a nutshell?

LAME sounds like exactly what I'm looking for, and I think I may have even had it installed when I was actively playing a year or so ago.

See here http://www.gamesas.com/topic/814477-magic-overhaul-comparison/ for a detailed comparison of the options.

Ah, thanks again

That comparison link is pretty good for a brief overview of Supreme Magicka and LAME. Note that SM is configurable with an ini file, while LAME is not. Overall they play very well together even if there's quite a bit of overlap. There's also http://theelderscrolls.info/?go=dlfile&fileid=215, which has it's core feature is your magicka pool & regeneration, and balancing the birthsigns, powers and races. The new races & hairs etc are extra. RBP & LAME are made for each other.

For mods that AREN'T overhauls:

http://oblivion.nexusmods.com/mods/25616 and http://oblivion.nexusmods.com/mods/25844 both let you attempt to cast spells above your mastery level and make magic use more...interesting. Both give a chance for the spell to fail or backfire. I'd recommend reading the descriptions as their mechanisms for backfiring are quite different. I use both together, and recommend them. But I'll note that it took some serious ini tweaking to get them to play nicely together and not end up with serious overkill on the backfires. (-30000 fatigue hit for failing to cast a flare in the tutorial dungeon?)

http://oblivion.nexusmods.com/mods/42658 has become essential for me. Includes some really cool features, but the telekinesis fix alone is almost as vital as the Unofficial Patch. And the elemental fists and the cast while sitting features are great. All the component features can be enabled or disabled in the ini file.

If you're interested in something completely different, http://oblivion.nexusmods.com/mods/37894 offers an alternative magic system outside the mages' guild, with custom summons, shapeshifting etc.

I'm aware that you've recently installed FCOM, which includes as part of the overhaul changes introduced through OOO.
Being a purist (and ever so slightly biased ) I'd give it a chance before what would obviously only in my opinion be overkill and unbalancing with the addition of a magic overhaul.
What ever you decide though, the main thing is that you enjoy and mod it to your prefereneces..

As always though, have fun doing it your way.