I like this idea. I don't think it needs to cover the whole wall, what if it was just a strip that went along the wall. The whole wall seems to be a bit much from the pictures (not sure what it would look like if you have the other three plain walls to offset).
Oh and Greg, a few more comments. Love how you changed the furniture. But I still see the flyers' reflection in the glass case
Matt, I like the first one with the giant coins, especially having nice toners in there. Since you can take high res images, you will need that for the file sizes to blow these digital files up to this scale and still look nice up close. In the image gbroke created has a good idea in it, you might put your store name up on the wall, say in white letters over the large coin images, if you feel there is a way to incorporate that without looking too messy over the coins. Does your shop have it's own logo/identity or specific type-face you use for ads, signage or business cards and the like? Something like that to tie it all together would be interesting. I agree with Doug's idea to wrap the door (and door frames) too, for a seamless look to the wall. I would also add the idea to minimize hanging anything on that wall if possible.
I think vinyl wrap is tacky (no pun intended). I would paint the wall beige, or an offset darker milk-chocolate brown and put up professionally framed images of coins, notes, and/or historical photos of the US Mints, etc. Painted lettering or decals of your business name on the left would look okay if professionally executed. Just my opinion, but floor-to-ceiling vinyl print would scream pawn-shop / white-trash to me. I would also ask the loitering geezer on the right to leave....promptly. He's scaring away all of the customers.