I always find spill from cymbals a problem with 421s.
Their off-axis rejection isn't the greatest. They do sound good on the toms themselves (about the only thing I like 'em on, honestly) but the rest of what they let in is a little wonky. 441s are cool, if you have/have access to them; much tighter pattern on those guys. Awesome under the snare, too. Never had enough floating about to use on anything bigger than a 4-piece.
'S one of the reasons the M179 gets recommended a lot (besides being the poor man's 414 in general)- ability to switch to a hypercardioid pattern. I've used Beta 58As here with good results for that reason (and because there were a bunch of them around). i5s will work.
Most of the usual suspects will work. I've had good luck with 604s on rack/602s on floor. D112, RE20 on floor, LDCs in general- LDCs in general on everything, really. Never tried SDCs on toms, honestly; I've heard of KM84s for those who have access to them, Oktava 012s yielding good results for the rest of us.
The more toms the drummer has, the more likely they are to get 57s because that's what there's the most of.