My first handgun was an H&R 732. I still shoot it regularly, and it is the one handgun I am the most accurate with. Of my handguns, it is the only one that's actually killed anything.
The first handgun that I actually purchased for myself was a service size Springfield Armory XD9. I let some peer pressure get the better of me on that one, as I really knew nothing about semi-auto's what so ever at the time of purchase (shortly after my 21st birthday). I ended up not really liking that gun, both because of the size and the caliber. Ended up selling it to someone who liked it more than I did, and don't regret it one bit. Since then I've shot a variety of different handguns, and I've learned a couple things.
#1: I don't like the grip on most of the service sized semi-auto's, I prefer the grip on the "compact" or "subcompact" models, as they fit my hands more comfortably. For example, the grip on my XD40-subcompact feels much better in my hand than the XD9's full size grip ever did.
#2: I don't like the 9mm in any handgun I've shot it in.