I've been fortunate to have had a number of dream bikes in my stable over the years. They have all been pure race bikes though, minus a Specialized Rockhopper that was my first "real" bike that I purchased. (LBS bike). I've gone custom, small builder, and big builder, and everything in between.
That being said, my current race bike this year, is the most solid, stable, stiff, G'up and go ride and it blows me away every time I ride it. '12 S-Works SL4. I'm coming off last year's race bike an '11 BMC Team Machine SLR01. If I had to pick one bike that I haven't ridden, there is something undeniably classic and sexy about the Colnago C59 Italia, buiilt up with Campy SR11 and Lightweight Obermeyers!
Something like this. (just found this image on the web, I'd take it as is, but...all black and with the Campy SRM.
My current build
'12 S-Works SL4
SRAM Red Black w/Quarq (53-39/11-25)
Enve 45 Wheels
Michelin Pro Race 4 Tires
3T Cockpit
Selle Italia Kit Carbinio Flow Saddle
Elite Paron Cages
Speedplay Zero Ti Pedals
Last Year's Bike: