I had Tiagra levers and couldn't reach them from the drops for anything--I have really short fingers. I ended up changing my bars to the short-reach Bontrager FIT (similar in shape to the FSA bars that aicabsolut has mentioned), which helped a little but I still couldn't comfortably reach. Ultimately, I needed the combination of the short-reach bar and short-reach brifters with a shim (Shimano R700) to get enough reach to get a solid grip (i.e. more than one finger) on my brakes from the drops--descending became a far more fun and less harrowing experience after that.

There's another discussing of this stuff here:
http://forums.teamestrogen.com/showthread.php?t=23110