Originally Posted by Chombi1

I always recommend the JPR (J. P. Routens) micro adjust two bolt seatpost. The two bolt pivoting mechanism provides the finest angle adjustment like you see on zero setback seaposts, but the JPR has the typical setback needed on road bikes. Enough of them pop up at eBay that it shouldn't take too long for a good priced 26.4 to come up for sale (The one in there right now is way overpriced).
The clamp on the JPR also clamps nice and tight, I never had saddle rails slip on them, plus the angle adjustment cannot slip either like many serrated pivot single bolt designs tend to.