I wouldn't go nuts with it, because it is a standard small bathroom.
Go with basic floor tiles for the floor (popular tiles are cheap for a reason, because it works and they can sell it volume), and not overly done with walls/backing (no tacky/busy design).
Yes, I've seen the green glass tile stuff. It's a fad. I highly doubt that it will stand the test of time. In fashion today - tacky in 5 years. I asked my wife who seems to be pretty good when it comes to design - I didn't prompt her, and she gave the same answer. "It might look nice now, but it's going to make it harder to sell the house if you ever decide to sell it." Your fashion friend is correct - someone WILL buy the house because of the tile. Everyone has different tastes. However, I think you'll end up losing about 50 sales first, before you find that rare someone.
It's a bathroom. igas's response really can't be beaten. Go with neutral colors - and it'll also be cheaper to go that route. You can add personalization, accent colors, etc., with other decorating things that are far far easier to change a couple years down the road. You can get that really tacky fish wallpaper if you want. Next year, a day of work and that wall paper could be removed and replaced with the newest style. If you paint the walls, you can go with all sorts of colors that would match neutral colored tiles. And, you can repaint every year to a different color if you wanted to. Get that green glass tile & you're locked into that color until you decide to spend another small fortune to have the bathroom redone.