Very thoughtful replies from the group!
My two cents:
I would hope the two of you would decide on a pattern you liked, first. And if you aren't remodeling the entire room, choose colors that will not fight with the present color scheme (common sense, right?)
I would also ask if there are any colors he really dislikes (my husband thinks red is for women, so he avoids it, but maroon or burgundy are fine. And since I told him how nice he looked in his pale peach shirt, he wore it frequently)
I wouldn't rule out every floral in the world; just don't use large pieces.
I'm attaching two pics. The flying geese in flannels was for my son, and it was based on the colors of a rugby shirt that he really liked (also a color combination someone mentioned here). I just added some lighter/darker shades, and chose various prints (which may not show very well in the photo); the krazy quilt has some florals in it (not what you'd see in tapestry or upholstery, but they have flowers in them), and one of my uncles just loved it. So, as someone already pointed out, every man is different!
Good luck, I'm sure you'll find the perfect answer, and please post a pic when you've finished it!