I've been really into aluminum frames lately. I had a few carbon frames break due to crashing in races, and got really sick of it. On top of that a close family friend was actually killed when his carbon frame failed on a descent. Carbon is perfectly safe (not starting that argument), but that event gave me an uneasy feeling when descending. The only carbon frame I still own is my 13.9lb Neo Hyper (really sick bike), mainly because I can't bear to part with it, and the performance is incredible.
My other three bikes are a Giant TCR SL (2012 Taiwan version), a Pro-Lite Carrara, and a Velocite Selene. All alloy.
Giant TCR SL = WIN... amazing bike, stunning looks and performance, 15lbs with 50mm tubulars and SRAM Force; too bad we can't get these in the US
Pro-Lite Carrara = everyday bike; SRAM Rival & Reynolds Attacks; <16lbs
Velocite Selene = VERY STIFF; SRAM Force... 16.5lbs built with heavy components/wheels, but strangely doesn't feel "fast"; bombproof though
When searching for good alloy frames I put this list together; cataloging frames that I found during my search, although I left out some of the more boutique builders... not that I didn't consider them though (Tsunami, Spooky, Rock Lobster, etc).
After riding quite a few alloy frames, the tapered head tubes offer noticeably better handling, so I only considered those; maybe naive but figured this was the "safe" route to go based on experience.
The Pro-Lite Carrara that I own comes in a 44cm frame (I ride the 49), and honestly it is the most comfortable of all my frames. I have it built with Assault Clinchers w/Pro4's, Ritchey Evo Curve Bars, SLK Stem, S950 BB30 Crank, e*13 BB, Tektro R741 brakes, SRAM Rival shifters, FD, RD, and SLR atop a P6 Carbon. At under 16lbs, it makes a great everyday bike... It gives up a bit to the TCR SL and Neo Hyper... and the Selene, is well, the Selene... about as unrefined as it gets, but damn it is durable and insanely stiff.
For inexpensive non-tapered frames, I'd look at Planet-X and Ribble as others have mentioned. They seem to have a great selection and great prices.
In the future, a Gualzetti Corsa with full Enve is on my list. When I'm independently wealthy, of course. Although, I think the TCR SL with the 1.5-1.25 HT is possibly the best alloy frame available right now... though haven't ridden the Canyon Ultimate AL.