Here's an idea for a small bar in a corner that you could close off with beautiful draperies. The second photo shows a pretty bar cart which could hold the necessary items, and the third photo is of a simpler butler's tray.

Seems weird not to incorporate it into the design -- I'm all about having things "look intentional" rather than working around them later. Like could the island have connected to this, rather than extending past it? or been L-shaped, so there's room for an extra stool, and also a wall cabinet? Anyway, hard to discuss that in the abstract without kitchen plans. I'm with miacometlady's original advice to not worry about it right now, and decide how to deal with it once the bulk of your kitchen is in place. You might find that you hardly notice it, with all the beautiful new finishes, or it might seem obvious to put some stainless or glass shelves there, or maybe simple is best and one simple hanging picture does the job. Don't stress about it until After. :)

I'd put in a tile backsplash. Stick with a solid color tile so your bottles won't get visually lost. Solid color doesn't have to be boring, look for interesting shapes or textures, and play around with different colors of grout to make a statement. The one in your picture looks very similar to the 2nd picture below.

Better to open both the doors... make a sliding door. Better than a mirror look for clean half white colour paint or laminate for wine storage above. Put more of ceiling lights to see highlight the niche for easy working. dim light are only used where a person is seating to have his drink and not at the place where he store the bottles...