Skidding on a bike probably won't stop you as fast as resistance and a brake because when skidding your weight is typically going more forward... less weight over the back wheel = more likely to slip and brake (see what I did there?) traction which means it isn't stopping nearly as effectively.

I believe resistance and seated/near seated skip stops is probably the best brakeless stopping technique. But seriously, just run a damn brake - may never know when it'll come in handy.

Tyres: I thrashed through a Vredestein Fortezza SE and a Hutchinson Flash (both coloured blue) before learning/realising these things aren't so made for skidding to **** on city roads. I've got a Continental Ultra Sport kevlar on there now, which was cheap from MEC ($15CAD) so I'll stick with these until my parents bring me the Vittorias I ordered from ProBikeKit in the UK.

In short, if you're trying to stop - don't skid so much. If you are just skidding, just use cheap crap you don't care about - skidding through and flatting is no fun, especially when you're on the way to work one morning. If you're wanting to stop effectively using skips, get a thickass and/or cheapish tyre as mentioned above like a Gatorskin or something with a thick tread/kevlar/re-enforced bead or something.

YMMV, as always.