I usually consider anything above 85 as good, I am mostly satisfied if I get 88 or 89 and anything higher is exceptional. I don't think I ever rolled more than 93 or 4. But for fighting classses such high roll is bit meaningless anyway.
I also think it is easier to get higher rolls with some classes than others. Ranger ie. I think gets higher max rolls so he should roll higher totals on average.
Ranger has minimum values in some stats. If the stat rolls lower than that minimum, it is auto-bumped to the minimum, but you can't pull points to make a stat go below the minimum (CHA can't be a dump stat for a Paladin).
ok so i'm going with 95 do to a few facts one imoen has a roll of 87 and if what i hear is true and I'm the son of.....you know.... i think it would make sense for me to be stronger then other humans.
Next i picked a fighter class and from what i hear they often get bigger rolls anyway.
I found a chart
Fighters, Clerics, Thieves, and Mages (straight, not any of the sub-varieties) can have some of the lowest roll totals because of the low minimums in most stats (each of these have a minimum of 9 in their primary stat, and minimum 1 in every non-primary stat). So theoretically, you could roll a Human Fighter with a 9 Str and 3 in every other stat (3 being the Human minimum), though this is only slightly more likely than rolling almost straight 18's.
The Ranger seems to have the highest in minimum stats (two 13's and two 14's), followed by the Paladin and then the Bard.