$400 won't by much new, so if you're looking for speakers in that price range, look for a used set of Yamaha Club 4 or 5s (S115 or C115 .. stay away from the SM and BR lines .. the drivers aren't as robust) or maybe a JBL MPro 215 or 415 (if you find them cheap enough). All sound great, are built like tanks and are used by a lot of folks. What you'll lose is the low end you get with a sub, but if you can't fit it, you can't fit it. You can always add a sub again in the future.