A vintage JBL with at least 10" woofer. Like this:
http://www.audiogon.com/cgi-bin/cls.pl?spkrfull&1229814086&/JBL-L200-Studio-Master-1970's
http://www.audiogon.com/cgi-bin/cls.pl?spkrfull&1229814086&/JBL-L200-Studio-Master-1970's
IYO, Best speaker for rock music under $1k