If I was going to go full "modern" it would be a top shelf asphalt smashing carbon bike, but I don't even know enough about them to tell you which one I'd want, but I would be interested to see how much of a difference a premium bike would make with regards to speed than my current stable of bicycles.
For the most part I ride a bike to get hurt a bit, so a less efficient/slower bike actually makes more sense, but I am a math geek, so more ground covered per effort is appealing to me, but, m'eh, I have little desire to throw money at the bicycle industrial complex....