I agree with sasha... CDT EF's (carbon fiber or fiberglass model only) or type X in that range, however try to have a listen to the type-x before buying, they are bright and some people find them quite harsh, theyre a "love them or hate them" kind of model... but like Tom says, front speakers aren't something to skimp on and $100 or so more will really give a much nicer set... above that point it's exponential for performance/dollar.
A set of CDT Audio HD-62's or Pioneer PRS's would be in that range and are truly amazing speakers for the money.
Even then though, you'll want an amp capable of sending them the signal they deserve to make them sound right.