Diff, do a search here and you'll find that some of us are using the BX5s+sub with excellent results. I use a $100 Wharfedale sub although the dedicated M-Audio sub would certainly be the best fit (but an expensive one). The nice thing about these BX5s, beside the solid mids and highs, is the selection of room-adapability switches, including one for easily adding and integrating a sub. Search for M-Audio BX5+sub both here and via Google. For $200, the BX5s are a sweet deal, but I'd plan on at least another $100-150 for a sub to produce those low freqs that any small speakers just can't offer. You'll end up with one heckuva low-cost monitor system.
J.