HK UMP .45 ACP is my choice!
Not because it is full auto, but because of the modern construction, light weight, short barrel and folding stock...it would spend most of it's shooting career on semi. Trick it out...add a suppressor(which could be transfered to one of several .45 pistols), mags, surefire, reddot.
I'd be quite happy with that combo.....but the class III dealer needs to have 'tried' to sell it to a LE agency before I can get my hands on one.
I have played with the Thompson, UZI, GreaseGun, Mac-10 and MP-5(not to mention HK G-3, M-16A1, M60 and Ma Duece); but for portable enjoyment and practicality the UMP fits well into my arsenal.
I like my AK as a Semi, and it is tricked just right for me, so it do most of what I need done.
AWB sunset....time for a Galil folding stock!!
Jercamp45