One thing I rarely see is unique models representing a sergeant in a troop squad. Typically, folks model up their sergeants off the same sprue which the rest of the squad came off of. This is something I used to be guilty of as well. Ok, ill give the sergeant a nice shoulder pad, a white helmet and call it a day. Well, I would highly recommend spending a few extra $s to really get that neat sergeant model. For me, it was a Vanguard Veterean model to act as my assault marine sergeant. Sure, it took a little converting (chopping off the plasma pistol, adding on the power fist), but I think it was well worth the effort. Well, we all dont have 45$ to spend on a metal box set Ultra Vulkan... Well, either do I, which is why eBay has become my best friend for buying individual models. Here is the tactical marine sergeant:
I was able to pick these models up for about 5.50 each off ebay, with a few extra to over shipping. Spend the extra 20$ to really add some flare to your sergeants, I think it will make any decently painted army really stand out.