Boomy bass in a room like that is a very legitimate concern. The ideal answer is to experiment and compare, but that isn't always feasible. If you have a chance; why not borrow some high quality monitors with a bit of bass to them, and see how close they come to filling your room adequately. Possible candidates, if available; Reference 3a Dulcets, ProAc Studio 110s, Neat Motive 3s, several Dynaudios, Monitor GR 10s. I've gone back and forth over the years in a room that's a little smaller, but I always seem to come back to the monitor approach as better overall....
happy hunting
-paul-
happy hunting
-paul-