Nebula

Don’t know what would look good on your wall? that’s okay neither do I but i can help.

what paper should i use?

A glossy finish will have an ultra-smooth, shiny appearance that makes images appear colour-rich and vibrant. most venerable to fingerprint this should be handled very little and hung in a picture frame.
Luster photo prints are a hybrid of glossy photo prints and matte photo prints. Luster photo prints have rich color saturation that gives a vibrant color finish and, like matte photo prints, they are not vulnerable to fingerprints, whereas glossy photo prints are prone to fingerprints.
Unlike a glossy finish, which has a shiny surface, matte photo prints have a dull, flat finish. great for black and white photos! In other words like your ex's humor its a little moody and wont smudge from finger prints.

what size is best?

well that depends on the space, now as the artist I get a kick out of printing the largest print possible but lets be reasonable about it. ALL sizes are in Inches so get out your grandmas old yardstick and measure it out! now remember unless you are getting a frame that has no boarders account for an extra 1.5-5 inches extra.