I like grapeseed–it’s expensive but you only need a tiny bit and it has no flavor at all.
Cornbread. Cornbread is why I have a cast iron skillet in the first place. Seasons it up all good, essentially requires the properties of the skillet, and very little cleanup. None, really - just wipe with paper towel.
Cornbread seasons the pan? I assume that’s from the Crisco (or whatever) you put in the pan before the batter?
I agree about the cleanup. The cornbread just falls right out of the pan, and a quick wipe with a paper towel cleans out the crumbs. But I’ve only ever made it in an already-seasoned pan.
Cornbread. Mmmmmmmmmmmmmm. 
ETA: doh! Zsofia beat me to it. Cast iron skillets were freaking invented for cornbread weren’t they? Or was it the other way around? Either way: mmmmmmmmmmm cornbread.
There’s oil in the cornbread.
I’m adding a step, then.
My Grandmother taught me to make a paste of crisco (or any oil) and salt (regular table salt) and rub down the pan with it. Then put it in the oven and leave it there - even as you heat other things.
I use the same paste when I clean it, rinsing now and then with hot water but only when it’s unavoidable. Udualy if I have to rinse I use liquid oil, then scrub with salt paste and place back in oven.
Before cooking just warm it until the oil is liquid and pour off the oil and salt.
Cornbread is my only use for it too.
Maybe it’s just me, but I don’t really get the allure of the cast iron skillet just for its own self. I have one, and like the last few posters above me, I make cornbread in it. And I guess it’s an acceptable all-purpose pan to use when you’re starting something on the stovetop and finishing it in the oven. But you can’t deglaze it or make a pan sauce in it, it’s a pain in the ass for all the foods that you can whip out with a non-stick skillet (like eggs and pancakes), you can’t really clean it, and it’s heavy as hell. If you don’t camp much, I don’t see why a cast iron skillet is better than your basic not-non-stick, metal handle medium fry pan. Is it because it’s cheaper? Because it lasts forever? What?
I do understand that some people feel the seasoned cast iron imparts a certain flavor mojo, especially to meats, but I seriously doubt I could tell the difference between bacon fried in cast iron and bacon fried in steel or copper, though again maybe that’s just me. Especially for a vegetarian, my respectful question is – why are you using a cast iron skillet anyway?
Because I have it. Once you have it, you might as well use it, right? My husband isn’t a vegetarian, so he can use it for meats, if that’s all it’s good for.
I don’t see why you can’t deglaze or make pan sauces. I certainly do.
Yes it does last forever and it becomes an old friend. Non-stick coated pans are fickle friends you have to replace every so often. The sorta non-stick coating on a well seasoned cast iron pan can be rebuilt if it gets screwed up. You can’t re-teflon your Calphalon.
Of course you can deglaze it. The carbon is tougher than the fond. Half a cup of cognac when you’re making your sauce for steak au poivre isn’t going to hurt anything. And they’re great for making gravy.
Cast iron heats more evenly and holds heat better than your typical non-stick pan. I can tell the difference between a steak cooked in cast iron and one cooked on non-stick.
As for eggs, I haven’t had any problems with them sticking. Why cook eggs in a cast-iron skillet? Because that’s where the bacon got cooked, and there’s no need to dirty another pan.
First off, what’s this about not being able to deglaze a cast iron skillet? That’s not true at all. Granted, I wouldn’t go dumping a bunch of vinegar in it, but otherwise it’s perfectly fine to deglaze cast iron.
Second, there is no pan that does a better job of searing. It retains heat extremely well, so dropping a large piece of meat into it isn’t going to result in the pan significantly dropping in temperature. It’s also spectacular at pan frying (say, chicken) for the same reasons. Ditto bechamel type sauces, where the addition of a large quantity of liquid is often necessary.
Granted, some people go a little overboard on the cast iron love (I would never use a pan that is so reluctant to cool off as my all-purpose skillet or saute pan), but it’s a fabulous piece.