gold.

I would leave it -- I think white will be even more boring. But since you are not thinking of it as an investment, how about distressing the wood (leave the canvas innner frame/mat as is) -- this could give it some real character. And if you donl;t like the result, you can always paint over it!

Another approach might be to blot it with gold (or silver) paint -- not "smoothly painted" but sponged on to give it an aged patina.

paint it a two tone color. make the inner border white and the outer frame gold or vice versa. it might give it more depth and a richer look

I would not use white. Gold or antiqued silver would be nice. I would just leave the linen liner alone unless you are interested in taking the whole piece apart and scrapping the frame entirely. I like this painting! I can't wait to see what you come up with!

metallic paint, bronze or dark gold

I vote for a silver and white combo on the frame.

I like the bronze suggestion. Something dark and rich, like that, would be cool.

What color does the wall have you are going to hang it on? If the wall is white, then I wouldn't paint it white. If your wall is neutral and you want something different why not a stained red, like the one in the picture? Might work (or could look awful, but might be worth the risk).
What every way I would consider your wall color.

i agree with gold.

Leave it alone - It's fine the way it is.

to brighten it up:
liner: bright white
frame: kelly green w/high gloss

My inclination would be to paint it matte black.

gold leaf it... available at craft stores like michael's ...they have copper leaf too..that might be another way to go...dunno how it would look in person though with the copper

I think the painting is too dark to go darker with the frame, and if you go lighter it's going to look very strange. I'd try to figure out how to live with it the way it is. And I'm NOT afraid of changing something to make it look better.

I used to work in a gallery and when people wanted to get rid of the 'antique' look we would rub the frame down with bee's wax. It shines it up and deepens the original colors. Try that first.

How you present the art has everything to do with whether people view the art as a "serious" choice for the room or they view it as a "campy" counterpoint. I think the aged and dark suggestions would lead one to the conclusion that you appreciated the more earnest qualities of the painting. Same with leaving it as is. I think wwoolsey and bisonbuffalo are on the right track. I only worry that the original frame may be a bit timid.

I'd darken the frame somewhat. If you're really into fiddling with abandon, try waxy black shoe polish rubbed on sparingly with a rag.

I agree with Nina79 - it all depends on the wall colour where you're going to hang it. If you're going for "campy" pick something funky, not neutral - you could pick out one of the colours in the painting, maybe even that pinky-red colour by her arm.
Happy painting - let us all see the final decision in situ!