you can do a dark brown, almost black color and make your hair longer on the sides for something new, but what you have is good. I know what you mean when you just want to change a bit for fun. You can always go back since it's you natural hair right?
This post has made me really want some roasted chestnuts *drool*
But I do agree actually, a darker brown shade would suit you well. Your current colour is also pretty nice.
Blue. No wait, red. Or purple. Maybe green?
Black. Definately black.
But seriously, unnatural colours require a lot of work and up keep so don't go that route unless you really want to. So far I've been black, blonde, blue, red and purple (not all at once of course. But that would be cool...). I would go for a nice auburn brown hair colour in your case. That way you can have a colour that's natural but still interesting. As for the hair style, maybe grow it a bit longer so you can have a fringe like this: http://hairstyleschat.com/wp-content/uploads/2011/07/Male-Hairstyles.jpg