It depends what Razor I am using but these three are my favorites to date:
1. Vintage Gillette stainless and super stainless (Smooth, sharp & long lasting)
2. Wilkinson Sword (German made, medium sharpness and long lasting)
3. Perma-Sharp Super (Smooth, sharp & long lasting)
Honorable mention to Rapira's. Dirt cheap, sharp blade but I can only get 2 full shaves out of them. I prefer blades that I can get some decent mileage out of but when Rapira's cost a third of the price of Wilkies or Perma-Sharp super's, its a mute point.
1. Sputniks, the regular Teflon coated ones seem to work the best for me and I can push them to between 6-8 shaves (which is a big plus when they're $30 for 100)
2. Personna Lab Blues, don't last as long as the Sputniks with only 3-4 shaves per blade but they're much cheaper at $12 for 100
3. Derbys, I get the same amount of shaves out of these as the Labs and they're the cheapest of the bunch at $9 or less per 100 AND you can get them in any Sallys for a fair price.
I only keep stocked up on 1 and 2, but I'll pick up some Derbys for a change of pace every now and then.
So far: PolSilver SI, red IP, and Shark super chrome. But I have yet to try Gillette Silver Blues or 7 o'clock yellows, among many others. Hated Derby and Astra SP.