My agency just recently started to allow the carry of personally owned weapons. Prior to that, everybody had to carry the issues HK USP. Firearms instructors could approve a P2000 for those with smaller hands.
You can still carry the HK if you want, which I do. You are also allowed a Glock 22 or 23, M&P, XD or XDm, Beretta 96, or some Sig variant. Since it is so new, the list is still being formed. I believe the specific requirements are that it must be a .40, capable of double action fire, with at least a 4" barrel and 6" sight radius.
"...you can't lose what you don't put in the middle... but you can't win much, either.