I need your advice!

So I bought this poster over a year ago (!!!) because I fell in love with it when I saw it in Domino once. Only I didn't consider the dimensions when I ordered it, and it's HUGE. Huge poster = custom framing = $$$$. Therefore, it's been loosely rolled up on a shelf in my closet for God knows how long (oh the shame).

Now that my credit card is paid off, I have a tiny bit of flexible spending money. I plan to take advantage of one of the crazy 50% off framing sales I've been seeing around as a little birthday treat for me (not until May!).
Here's where I need your advice. I dream of doing a fat white matting with 2 inch wide flat white frame... only I got that priced and even at 50% off it's like $200. So I want to go with something simpler (not wide mat and frame, just thin).

My obvious options:

Plain white framing, no mat

White mat, thin black frame
White mat, "natural" frame
No mat, "Natural frame"
White mat, thin white frame

I don't know!!! I'm too close to this to have a sane opinion. What would you guys do?

P.S. I'm not sure if this will go in my bedroom or living room yet, but the furniture in both is dark espresso... I have other frames in the living room that are black, but I also have one white side table, and the dining room (same space as living room) has a big pink flowery photo with a white frame. No art yet in the bedroom, but also have white side tables.