When you're as maxed out in level because of major skills as you can be, is it possible to take out every hostile creature/person in the game after all quests are completed?

Nope. There is an infinite supply of hostile creature/persons in the game. The Emperor had them secretly manufactured on Kamino and shipped to Tamriel at great expense for our entertainment.

Lol Thanks!

To be more specific, all areas in Oblivion respawn every three days. So there will always be something to fight in the game where ever you go.

Bravo!

And if you're running just vanilla, the level scaling will prove to be quite the handful!

With a 73 hour respawn rate, there will always be things to kill

I concentrated on Personality, Luck and Speed. I enchanted all the items the PC could wear and carry with Fortify Personality. I play in third person [back arrow gives spinning sword swing plus no more instant death from behind]. Because of the enchantments on top of Personality attribute, I seldom need to fight as almost everything likes me [plus passive wildlife mod]. All villains runs past the PC to fight my CM Useful Idiot Companions. With frenzy enchantment placed on vanilla guard arrows there is no end to the spontaneous fighting [simulating post Septim society breakdown]. Just stand on a high place and watch the action.

how high did you have to get your personality before enemies stopped attacking you?

Now that my game has finally gotten easier (thank you, Mages Guild recommendations!), I've a question about this.

When areas respawn, do the enemies in the area stay fixed as they do in Skyrim, or does only the "boss" get leveled with my level?

I'm asking because, south of Skingrad, I cleared out Bloodcrust cave around level 8 or 9. It was full of vampires, and while they were a little tough, I managed to clear them out. When I went back in again, it seemed so much easier, which tells me they're at a fixed level. The last vampire I took out was wearing all Mithril armor this time (which was good, because I was missing the helmet) and weilding the first glass weapon I've seen in the game.

However, when I entered another cave today (Magestic Cave, I think the name was), those vampires where much tougher, as I expected with my level. What made this noticeable is the enchanted bow I have, which adds 20 pts of fire damage as well as drain health 20 pts for 1 second. Using silver arrows, they still took several hits to take down. Well, except for two of them, which the 3x sneak bonus really played its part. Damn, do I just love fire!

No, they do not stay fixed. Scaled enemies scale indefinitely. And for the most part, the higher your level the more often you will fight scaled enemies. At level 55 you will, with some exceptions, be fighting level 55 enemies everywhere you go.

This isn't accurate. Many creatures in Oblivion have a fixed level. What the game does is introduce new fixed-leveled creatures throughout the game, though I'm confident this has its limit (perhaps level 25).

There are some enemies which do scale.

Traveling on the road, for example, you may run across a Minotaur Lord, who scales, and the fight will be difficult regardless of the player's level, but a regular Minotaur gets easier over time, especially as the player crafts better weapons and gathers strength in their appropriate skill(s).

Perhaps I wasn't clear. This is exactly what I said in my post. With one exception: there is no limit to scaling in Oblivion. In Oblivion (unlike Skyrim) scaling continues indefinitely.

Especially with the difficulty slider at 75 percent or higher

I first researched the before I bought it.

http://uesp.net/wiki/Oblivion:Attributes

I concentrated on maximizing Personality, Luck and Speed [for running away]. On top of that there is the Lover Stone and Fortify Attribute Enchantments. I chose to fortify every possible carry and wearable item with Personality. I also use 'Oblivion -Elys- Uncapper' http://oblivion.nexusmods.com/mods/13841; Yuda The Elder Trainer http://oblivion.nexusmods.com/mods/13889; and Galerion Natural Leveling http://oblivion.nexusmods.com/mods/41591; Companion Neeshka and 3 Chocolate Companions [who regularly beat the crap out Neeshka and each other] as my useful idiots.

While I am quite happy with my 360 and my imagination, it's these lines, where you can introduce politics and societal influences of the times, that I want a PC. Sounds fun OP.

Drain for 1 second... might be better off going drain for more seconds. By the time you have re-strung and drawn to full extension (just over two seconds) they will have gained back that health, and it would be the other enchantment of fire only, that is causing the damage. The drain will help when you have whittled them down a bit, by a shot or two.

I use drain a lot in my custom touch spells, when baddies get too close. Other than that, I do a different type of combination of enchantments for my bow, but these different combinations are always a result of the RP.

I always lead with Soul Trap for 2 seconds for my enchantments. Two other elements, too expensive for my tastes for all three. And some light. Holy light. Lights up the dungeon for a split second. Poof. That's just me on the current character.

For some entertainment, 'setav speed 200' on Ogres, Spriggans, Minotaurs, daedric creatures and bears. I also added Telekinetic Hammer enchantment from 'Telekinetic Mastery' to guard silver longswords.

But extra cost in seconds for a drain is too high.

This bow was expensive to maintain. I don't hoard, but I had to break my own rules and grab a few things to sell in order to pay the cost of it.

Thankfully, that's all over now. Soul gems are starting to show up in caves and I can repair enchanted gear.

So, with my new Daedric bow, I threw on 20pts of fire damage at 100% weakness to fire for 1 second, and vampires light up like a college frat party bon fire.