Just as the Title states, what's your choice in bullets for a barrel that has significant pitting? Do you find that sabots or conicals tend to shoot better?

I'll of course give it a good treatment of JB's but any other tricks you have found to bring a mistreated barrel back to life?

Sabots will do better in a pitted barrel .

Yep and as much as I absolutely HATE to say this, I mean it is seriously making me cringe while even think about writing it, PowerBelts seem to do well for those with crapped up barrels. Those new Federal BoreLock bullets MIGHT do pretty good as well.

If you want to try and remove some of the pitting you can make a slug for the barrel. Its easy to do. first put a wet patch in the bore about 5" down then degrease a brass brush of the proper caliber and put that in the bore leaving about 1/4 of it sticking out so as not to get lead on the threads. Get some lead good and hot and pour it down the barrel enough to go all around the brush. The lead will cling to the brush but not the steel. Let it cool and when you pull it out you will have a slug just for that bore.
You can use it to lap the bore with the JB compound. Just be sure to line up the rifling when you put it back in. (don't forget to take out the patch).
Take extra care if you have a fiber optic front sight so as not to get any hot lead on it or it will melt. I would wrap a wet cloth around it.

Sabots seem to shoot best out of a badly pitted barrel. Although I have a White Bison that is in bad shape (not by my hands) and it still shoots conicals very well.

OK just my 2 cents here, BUT isn't shooting out of a badly pitted barrel also a safety issue to have some concerns about!
Maybe replace the barrel and do a little better on PM care!
as pitting can lead to weak spots NO?
and I am NO expert here, just throwing this out there!

I think it depends in the degree of pitting and rusting. And you are right, if you have any doubts take the gun to a qualified gun smith for inspection.

When I was given an very bad pitted rifle, I cleaned it as best I could, trying to get the rust out and some conformity in the barrel. I was told it used to shoot 90 grains of Pyrodex and a round ball real well, so I began testing the gun from 50 grains and then up. At 70 grains I got amazing accuracy with a patched ball. And never went any further.