I just got a Cannondale CAAD7 off of craigslist for a "beater" bike. I am a fan of aluminum (I ride CF-steel etc.) so I know what to expect.
I took it on a spin, and it absolutely blew me away. I stripped the Campy Record (2002) off of a Pinarello, and I am sticking it on a $225.00 craigslist bike.
Awesome "old" aluminum is still awesome.
Now I know why people go crazy for CAAD frames.