What I'd suggest you do is either to go to your LBS and ask for a test ride on a bike with Campag, Shimano or Sram. Or if you have some friends with some of these try riding their bikes for a little while. I much prefer Shimano over Campag/Sram but if you find out which you prefer then it'll narrow down your search a bit and you'll end up happy and not wondering whether you could have gotten a comfier lever.
What I'd suggest you do is either to go to your LBS and ask for a test ride on a bike with Campag, Shimano or Sram. Or if you have some friends with some of these try riding their bikes for a little while. I much prefer Shimano over Campag/Sram but if you find out which you prefer then it'll narrow down your search a bit and you'll end up happy and not wondering whether you could have gotten a comfier lever.