Does gear buff mana regen in combat? If it doesnt, I have waaaay to much regen... 240% just from gear, another 25% with the resto talent

No mana doesn't regenerate in combat.

It does.

It does indeed. But the thing is, in combat regen is a very very small fraction of out of combat regen. Increasing a very very small number by percentages will probably still give you a small number.

thats what I was wondering. if its a flat rate for everyone or gear based

Its gear based. For example, if your in combat regen was something like 5 magic/sec naked, and you found some gear that would give you 100% additional regen, you'd have 10 magic/sec. Some advise though: If you have to pick between regen or a decrease in spell school costs, make sure to always take the latter. You'll never get enough +regen to ever make a difference in combat.