@Anonymous1502 some of your needs seem similar to mine. My criteria are these, in order:
- must be a very good fit for me only needing minor adjustment, not a make do by changing x,y,z
- comfortable over long distances
- help me achieve the level I need to stay with riders perhaps 20 years younger
- look good - this is very important to me
After meeting those criteria I would have to include high quality wheels and disc brakes. Good wheels, for me, are worth 2-3 mph on the flat, more when descending. I like the faster braking discs give in an emergency but this is rarely called for. Again for me the real benefit of discs is I find they give me greater control, a very light application will gently vary my speed just enough. I find this gives me greater confidence.
If money was no object I would happily put it in to the very best components. However I do have budgets so for example would chose 105 over Ultegra and put the saving in to wheels and tyres. I don't believe 2-300g less weight makes a huge difference at my level. It's cheaper to shift a couple of kilos off my waist.
Once you've set a budget I suggest you create two lists of essential and desireable. Once the essential is ticked off with the very best you can afford move on to the desireable list.
My current summer bike was £3000. A year later my LBS handed me two wheels and said these will make you go faster. Cost me £600+ but boy what a difference.