I personally love it on a plain band. It is SO elegant. The pave split shank would bling it up, but in my opinion, it would actually end up complicating and confusing the look, detracting from the beauty of the stone. It appears to be a very large diamond....it needs no other accompaniment! Emerald cuts, especially, look best in an uncomplicated setting because of its clean lines.
After you're married, I can totally see your ring as a solitaire with either a matching plain platinum band (very classy look), or if you want to bling it up, I'd do it with a thin and understated pave wedding band. Or heck, get both so you can have a choice every day!
CONGRATS ON YOUR ENGAGEMENT!