Bet thing to do is get out there and try a ton of bikes. It can be a daunting process as let's face it, no one has a lot of patience for looking and trying, you just want to find something and ride!
But take your time, make sure you really like the bike and the most important thing of all is to get fit once you purchase the bike. It makes all the difference in the world in terms of how much you enjoy the bike and also avoiding injuries. While your BF may have some suggestions, remember you're the one that has to ride it. If you don't like the bike it will be a waste of money.