Unless you're looking for a bike to take with you for all eternity, a Ti would be recommended, I suggest you base your criteria on something other than frame material. $2000 is a lot of dough to plop down for a rider that just rejoined the fold after a 8-year hiatus. How enthusiastic about cycling were you before you took time off?

My point is to take is slow. Discount half of what you've read here. The poignant praise of the new 105 group almost makes me think that I would be miserable with any other components yet there's scant difference between bikes equipped with 105 and those equipped with Tiagra (or Ultegra for that matter). Component groups mostly just get carried around. You'll win more smiles and winks from "experienced" (read well-healed) riders that approve of your choice. But is that what cycling is really all about?

Take time to think about your priorities. I think there are bikes out there that will offer you the headroom to really grow as a cyclist. BTW, I think the CAAD8 is a better choice for most recreational road cyclist because it includes a slightly taller head tube and more relaxed angles to make the bike more comfortable to ride long distances. I know there's an endurance category, but you needn't search there for a solid road bike. CAAD8 Tiagra, that's my recommendation.