These came free with a GW Paints Starter set, circa 2000 I think, when I was trying to figure this three-cell painting thing (shade, base colour and highlight). The "feathered headpiece" dude was a Space Marine Captain that I gave to my nephew to supplement his "Space Crusade" game. It ended up returned to me when he was de-cluttering his bedroom in favour of FHM/Loaded poster girls and the like. Was I the real winner here? Probably not.
When you "Dust-Down" on a remote planet the other side of the Galaxy what happens next? You stand around the Captain looking imposing, alert, ordnance at the ready waiting for something to pounce on you. When it doesn't you make a big safe and cosy "Space Tent", post a sentry and the rest of the squad make a "brew".
Naturally the sentry gets careless, just as something dangerous, with large teeth and animal cunning turns up to spoil the party. Oh here's one now:
I was always more of a Sci-Fi RPG collector rather than GW Codex Army builder and "the space" stuff is kind of fun to put together and paint with no historical boundaries to observe. If I were going to build an army/force of space things I would be more incline to go 15mm as there are some excellent manufacturers out there.
Footnote: I just realised I took the photographs of the grunts from the wrong side. rather than showing that the 40K world sill uses 21K numerals, I could have shown that they also use 20K insignia in the other shoulder.