Thanks for the heads up on the compensated. I'm new to handguns so I don't know much about them... For now I will most likely be using it for home defense and normal range duty.
Compensated barrels, slides, match weights, etc. are best suited for competition. Besides, for your home defense gun, you really want it to be a non-customized off-the-shelf handgun that you get really proficient with. For one thing, if you do ever use it, it will likely be confiscated during the investigation, and you can be sure that in the evidence room it will not be treated with the same care you will.
If you ever get it back, that is.
Get lots of practice with a standard USP, P30, HK45, P7, or whichever other HK handgun you want. After you get proficient with one of them, then you can try out some of the fancier features, but you will still be better off learning to use one of the normal ones first.