I'll preface this by saying that I've been a mountain biker for over a decade, including XC racing for a couple years. I've never had a hard time adjusting the saddle angle (tilt forward or back) on my mountain bikes.
Now, I just got my first road bike, and I can't seem to get the angle to feel right. The seatpost is an Icon Graphite series (single bolt adjustment, but has notches as you angle the seat fore and aft). Saddle is a Selle San Marco (Trek 'postal service' design).
It seems that at one seat angle, it feels fine when I have my hands on top of the bars (on brake handles), but when I'm in the drops, its not so comfortable on my "soft bits", and I find myself lifting myself slightly off the seat with my legs as I ride to keep the pressure off.
Alternatively, if I tip the seat 1 notch forward, then I feel more comfortable in the drops, but when more upright on top of the bars or on the brake handles, then my butt slides forward.
I guess this just has to do with the change in body angle from being on top of the bars to being in the drops, and wanting the seat to be at a different angle for each position. Since on my mountain bikes, you don't really change your whole body's angle that much, I've never had this problem before.
I though maybe switching to a 2-bolt style post might help because I could try to get it adjusted into a "sweet spot" basically at an angle between 2 notches on this Icon post, but the Icon post is also set back slightly, whereas a 2-bolt adjustable design puts the seat directly over the tube, so the seat would be slightly more forward then to begin with...