Years ago I bought the super-trashy Hasbro Death Star Trooper, for the specific purpose of using its helmet and suit to make a nice custom figure. With the arrival of my new Sideshow Darth Vader, I finally got around to it.
The helmet looks surprisingly good as-is, although I wish it didn't have the tiny molded dents or 'battle damage', although these are barely visible. Overall, the helmet looks great. It's the perfect size, and it's quite film-accurate. I used a cigarette lighter's direct flame to add a good shine to the helmet dome and flare, and that worked very well. (don't burn it near the edges!)
I gave it a good new articulated body, new leather WWII German 'Jack' boots (modified) a Sideshow DH17 blaster, a custom-made leather holster, a custom-made belt with polished aluminum buckle and utility boxes, and for the gauntlets, I used the glove hands that came with the Hasbro Garindan figure; they were just the right size, as opposed to the huge cartoonish hands that came with the original Trooper itself.
I have a sewing machine, which I put to good use altering the suit; I thinned the sleeves and pant legs, and fixed the extra large collar to make it nicely tailored to fit the new head/neck. I made a new chin strap and chin guard, and *poof* DONE.

If you have a Hasbro Trooper gathering dust, I highly recommend this not-too-difficult custom. Next to my 14" Vader, it looks awesome.