My favorite MP5 look is the A2 stock combined with the earlier non-Navy SEF finger grip contoured lower. To me, something about that combo shouts out a counter-terrorist look using either the slimline or tropical foregrip. Also the A2 and early contoured SEF grip combo looks just dead on 'right' for an SD gun.
I do realize a lot of people prefer the look of an MP5 with an A3 stock and the pictographic ambidextrous Navy lower that I regard as the "Steven Seagal" look. I don't have the hair for a slicked-back ponytail though.