Ok, radical left turn on my hunt for the "fast & fun" bike here - I took a look at a Cannondale CAAD9 6 at my local bike shop, test rode it, and it seems very very nice. I think they may let me have it for something like $995, which seems like a pretty good deal (although California sales tax always hurts, argh). I think for my lightweight road bike I'm willing to forego steel. It's got Tiagra, which obviously isn't the best out there but I figure it'll do just fine for me, at least until I lose that 30 lbs of blubber around my waist. I figure if I really get into this then I can reward myself by upgrading the components, and it seems from my cursory reading around the forums that the CAAD 9 is a very well regarded frame to build on. People talk about the harsh ride, but it didn't seem unduly harsh to me - pretty much what I remember a road bike feeling like. It felt lively and wanted to "go fast", which is what I'm looking for here. I think I'm in lurve.
Thanks again for all the tips,
Neil