Depends on what you're looking for.
Here's a few examples in the under $500 category - If you want rockin' and thumpin' then vintage JBL's. If you want low level horn-y detail and dynamics, Klipsch Heresy's. If you want "Audiophile" quality sound - detailed, accurate, smooth, and non-fatiguing with decent bass extension then Dahlquist DQ-20i's (or DQ-20's).
Spica's - have a real magical midrange, but a pretty weak low end. Excellent for a small room, and bass improves if placed close to the corners. But in this vein - a used pair of Green Mountain Europa's should be considered, even though they're not "vintage".
Here's a few examples in the under $500 category - If you want rockin' and thumpin' then vintage JBL's. If you want low level horn-y detail and dynamics, Klipsch Heresy's. If you want "Audiophile" quality sound - detailed, accurate, smooth, and non-fatiguing with decent bass extension then Dahlquist DQ-20i's (or DQ-20's).
Spica's - have a real magical midrange, but a pretty weak low end. Excellent for a small room, and bass improves if placed close to the corners. But in this vein - a used pair of Green Mountain Europa's should be considered, even though they're not "vintage".