My advice for that money is to go 2nd hand. You can pick up a nice bike for that 2nd hand vs what you'd get new. But if new is for you then
Just make sure it has STI levers, clipless pedals and is sub 9kg's or so. A lot of what you pay for in the more expensive bikes is the carbon fibre frame/forks. My personal opinion is that most of the shimano gruppo's work great, even at the cheaper end. And the weight diff isn't so bad. You may need to get some no name Asian made frame, but stick with Shimano gruppo.
Also if you have a choice, go light with anything that turns, eg pedals, crankset, etc. Better to have a heavier frame, seat post, etc than heavier rotating parts as it takes more effort to turn heavier parts vs if they are in the frame.
At the amateur level if your going to win a bike race, your going to do it regardless of whether your on a sub 7kg bike or a sub 10kg.