Probably not a Tri bike, since I will want to use it for family rides.
Would really like to keep it under 2k. If after this year, this is something I get really serious about then I can pop for something on the upper end.
5'10 and 31ish I would guess.
For less than 2g's you can buy yourself a nice bike. I think for the 1,000-1500$ rage you would be very happy. You could go into most bike shops, buy something off the floor from last year and be all set.
You probably are going to be looking at 56cm frames.
Aluminum is the most cost effective material, but it can be a harsh ride. It is stiffer and has great performance, but your ass may have to get used to it.
Steel is very comfortable
Carbon is fine, but more expensive. You will get lesser components on a carbon < 2g frame.
Titanium is the best all around, but save that material for your dream bike.
Most time, the frame will be adequate on any bike over 1000. You want to concern yourself with getting the best components as possible. Ranked in importance
Wheels - you want light durable wheels. The only thing that makes a big difference in the actual performance of a pike (how fast) is wheels. Rotational weight is a huge component to performance and going up hills.
Shifting systems - SRAM and Shimano are the way to go. The SRAM systems are good price point
The rest really don't mean much.
Find a nice bike with the best wheels and shifting system and you will be happy.