Originally Posted by jfranci3

There's lots of options at your price point. Keep in mind that for all the talk, there's not much of a real world difference between everything. Where are you located?
In the US, typically Giant and Trek are the best bang for the buck. Current aluminum bikes from bigger brands ride the same as carbon ones, so I wouldn't even bother considering carbon at your price point. As far as quality, they're all the same for the most part. You can ride a lot of the 'wrong' bike before you start giving up anything - for example the best aero road bike is only 20w @ 27mph faster than a horrific one (looking at Tour Int tests) that's about 5% or .25-.5mph if you're hitting it extremely hard. Stock to good tires, good bike position, and good clothes will make a much much much bigger difference (assuming the same fitness).

If you've got one bike, I'd steer you toward an "endurance" or even "gravel" bike, so you can do some light off roading on a second set of fat tires. The penalty, again, is not high. I'd also suggest getting a cheaper old stock Tiagra over a current 105 bike or used bike, and spending more money on accessories (lights, shorts, seat, jersey, bottles, cages, glasses, computer...it never ends), as 10sp vs 11sp isn't much of a change. You're right on the gearing, just go with a 50/34 front chainring bike (pretty much every bike now). It's unlikely you'll need taller gearing. Also, IMO, paint job is more important than most things- spend money on the coolest bike.