Yes I am sure, and nope, I won’t be saying that 🙂 Just saying that aspects of them are a clear influence on the space marines armour. And now you come to mention Dune, that must have influenced the Imperium to a degree, especially in the film of it where they were wearing 18th Century style military uniforms in a sci-fi setting (like the Imperial Guard, check out the Vostroyans). And of course, The Terminator is a major influence on the Necrons, as is Ancient Egypt and the skeleton soldiers in Clash of The TItans, as in undead skeleton warriors. And Aliens (and to some degree Starship Troopers) is a clear influence on the Genestealers and the rest of the Tyranids. I’m not sure what you mean by saying “Intellectual property my arse” as I’m not saying they just copy everything, because that’d be stupid. If that was your intention, you could say they ripped off all the designers of military ware from WWI and WWII, since they too are a major influence on the Imperial Guard.
So did you mean that you think that GW doesn’t comply with intellectual property laws and that they just rip things off and stick their logos on it or something else?

I like how they weave different and interesting things together to create something that looks great and is interesting to read about, paint, and play a game with.

No one can design anything without being influenced by something else. All designers/artists/authors of fantasy/sci-fi things are all influenced by the things that they think is cool or interesting.
For instance, I’d only recently learned that author Michael Morcock’s books are an influence on the idea of GW’s Chaos, even down to the 8 point chaos star; have a look at this http://en.wikipedia.org/wiki/Symbol_of_Chaos ; Morcock had doodled the star to show someone what he thought they would look like. It doesn’t take a great deal of thought to see that someone at GW was reading his books and thought it would be cool to have a warhammer version of chaos in their games. Just as a someone may have thought it would be cool to have some design elements of the stormtroopers or terminators in there designs. In my own models, I thought it would be cool to have a catachan vet squad based on Predator. And although I’m not a company that’s selling them, there are influences of Predator in the Gunnery Sergeant Harker and his heavy bolter called Payback, influenced by Blaine’s minigun callled Old Painless.
There’s no need to get wound up about a simple statement that I always thought that those star wars costumes remind me of bits of space marine armour, and that’s it, simples 😛