How big is your bedroom? Is it a conventional 4-wall rectangle-shaped room? What wall is your bed on? Can you post pictures? I love dark colors. I agree that painting really small rooms dark colors can produce a cave-like effect. But, if your room isn't terribly small, sufficient lighting will keep it from feeling like a cave - most rooms need three (artificial) light sources to not feel oppressive. Years ago when I lived at my parent's house, I painted their living room a deep greenish-teal color, almost like the ocean when it's that deep glassy green. They were quite skeptical at first because the color was so dark, but they love it now. If you're not going to paint all the walls, I'd probably recommend painting the wall the headboard is against, and maybe that's the only one. Do you have any pictures? I also agree that neutrals would go well, but it really depends on the green you end up picking. You could paint the ceiling a lighter shade of the neutral you end up picking so the contrast isn't so great.
I recently did a bunch of renderings for a client who was interested in painting her guest bedroom green - I thought her favorites (at the bottom) sounded similar to what you might like. The bedroom renderings start about halfway down this post: http://hardtimesdesign.com/2012/01/2...m-and-bedroom/
Hard Times Design