Real Hunger and Real Thirst are prime examples of stat penalties for not doing busy work and, in my opinion do not transport the player anywhere but having to have the character carry more things. I've used a lot of these types of mods, but never for very long.
Duke Patrick's Hypothermia and less so his water drinking one are better examples of creating immersive visual and auditory cues as well as effects happening to the player - getting wet matters, being out in the snow matters - it serves to transport the player by doing more than stat adjustments (annoy the player) and providing a world to experience (more than visuals and graphics - well virtually more). My beef is that modders seem to want to handle only one aspect or another of immersion mods and as such that leaves the player to piece together the rest with a sometimes mish-mash of mods and settings. And the more mixed the more things like stat damage happen. Right now Hypothermia is the only one I swear by. I'm liking Realistic Health too.
If something like http://www.gamesas.com/index.php?/topic/1138872-wipzrelz-imps-more-complex-needs/ were made for Oblivion - I'd be first in line to test and use. Look at what it handles and with a more primitive script extender to boot.
This is a major lacking area of Oblivion.
Skycaptain and others-
Waalx Animals and Creatures is Alpha, it needs editing (I posted a few times about that on that forum), It might have a few issues when you use it with Wrye Bash, and as far as I can tell has been abandoned (though like FCOM the users there swear Waalx will return at any moment - even though I think he has been gone longer than Dev_Akm).
It is unleveled and has many spawn points (like MMM) and as such it doesn't really fit well with MMM. It has no bash tags (but those are easy to add). I'm using it with TIE (which also is unleveled and I think a better fit with WAC than OOO/FCOM - which is about some uber leveling complexity that borders on absurd at times). I find the animals great and they have good AI and behavior. Some are downright mean in packs (the fears especially).
I've pondered about compatibility and leveled lists - providing a mod does not divert leveled lists or delete them then mods should work with together with Wrye Bash - the issue becomes more about theme and style. I suppose being the author or such a mod one could read my statements and counter with 'but you are missing the complexity of these mods and with mod X combined with my beautiful overhaul/LL mod the creature list so and so embedded in such and such will be blocked by the lesser contents of Mod X. Probably true, but I don't care. If combining them does not cause ctds or break the game or quests and I don't get full and exacting expressions from leveled lists - then I'm cool with that. Bring on the green man from WAC and the uber tall Spriggans from TIE! They're perfect for each other.
If it works right 95% of the time that is more than enough rather than having to wait a year and a half to get a patch that only ends up drowning out one mod over another.
[edit] Ohh and there is an OOO-WAC patch - available on the WAC forums. I've not used it but I think the advise was not to use MMM too.
[edit] I really don't understand the point of this thread's Poll - what are you trying to do rate each mod? Better to ask what kind of overhauls preferred or what kind of realism mods preferred.