With the green walls I would go double or triple Irish chain.

I have made several quilts for men and it seems to me, as long as it does not have flowers, they are pretty happy with whatever you make. I've done baby blue and white, red, white and black, blue and black, turquoise and brown, etc. The only thing???? no flowers!

Living on the Gulf coast your room says water and beach to me in batiks! Think water, sand and sky- if you want more pizzazz than restful throw some sunrise (lighter) or sunset (brighter and darker) into it. Any of the already mentioned patterns would work, but I'm leaning towards Trip around the world. Post pics for us!

I like the green and white! What does he like!
Jenny's big star is easy and uses pre cut sqs. and she has lots of different quilts made from jelly rolls and other strip bundles.. I love the hidden well design. Jenny made it with strips, then cut sqs, lay two together with strips going opposite each other, sew around all edges of sq. and cut diagonal corner to corner, open, press, and sew those sqs together (either with x shape, or with sq center). When finished the sqs look complicated and impressive! With the right colors these blocks are very regal looking! I am making a quilt with this block that has brown paisley print with gold threads and red strips that would look great in your room..maybe put in a strip of hunter green.
Love to see what you come up with!

The first pattern that popped into my mind was Jacob's Ladder, with a non-floral focus fabric, a complimentary fabric with a white or cream background. Another choice might be a log cabin quilt. I look forward to seeing what you decide on. Love the green on the walls with the white woodwork.

How about a log cabin using the various shades of green and cream. I made a green and cream vertical log cabin for DH for Christmas 2 yrs ago, using a gold center block. I think it turned out o.k. It should be on the board listed in pic. as "Greens with White Sauce".

Quilt for husband
 

Sorry - forgot the link www.youtube.com/watch?v=Tkm3nCferp4

hunter's star was the pattern that came to mind when I started reading this post. I like the gray or carpet color suggestion too.

How about one of these I save pictures of Quilts on my computer when I might want to make one or need ideas and these are just a few I have saved if I can get them loaded

Batiks came to my mind also. I am in love with the jelly role batiks. You just can't go wrong with them. I love the Hidden Wells pattern and am making my third one (all for grandchildren and one is a boy). I love the pattern in HillCountryGal's post. It is spectacular! May be my next pattern. Also, my 11-year old GD just picked out a pack of jelly roles and the "racing" pattern. So easy, generic and beautiful. Good luck.