Just gotta search google for a bit. You could search for key words like concept art, notable travel spots, sci-fi worlds, map overlays or just anything you can think of that would bring up. If you have a blocked out map already, share a photo and ask what kind of theme's people would think it would fit. If you are looking for map block out idea's, the same thing applies or look at larger campaign levels or maps and build a block out of just a small section from it that would suit Halo well. Maps overviews for example google map overviews
1) I always like to base my maps off of historical areas. For example, I've done/will do a Greek, Roman, Mayan, and Japanese themed map. 2) Halo CE's architecture is beautiful... always a great starting point 3) @fame28 nailed what my third thing was gonna be
Nice. I kind of prefer the layout, size and scale of Morbias but I like the ideas of the death pit and shorter hallways. If you like UT game pacing you would probably like the map that I have in eternal limbo. It's basically done except for kill zones and tuning. If you download it, make sure to comment on the page so you get notified when I release the completed map. The true name is Baltis Causeway. Check it out. Back on topic - I often get inspired by sets in movies, though I seldom use them because of my preference for tighter maps. Just look for pretty much anything that is epic scale. I'll also scour google images for art.
Just think of something random. Just anything at all that you find cool. Like something you'd love to be in or experience. Sum it down to one or two words, and then type that word or those words into Google Images and look around. That's what I do.