I can't believe I didn't see this thread, I started off as a avid Mountain Biker, had a Giant hard-tailed Mountain Bike with Hydraulic front shocks, Shimano XTR Gruppe set, then I had a really bad fall which totaled the bike, so coupled with my back problems... I gave up MTB and went to a road Bike.
Started off with a simple Scott 8speed Shimano Tiagra gruppe set and an all aluminum frame which weighed in at 22lb's... after I wanted to get serious, I had to decide between a Litespeed with Campag gruppe sets (I personally didn't like the feel of campaq's gearing, felt so harsh and fragile) or a Fuji with Shimano Dura-ace Gruppe Set which only weighed 16lb's... ended up with the Fuji, it is really light, only thing about it is when you're going downhill at speeds (~50kph), you can really feel the lightness of the frame which can get pretty scary.