Do you want to use the mics for other duties besides overheads and if so what? Lots of mics are suitable. I've used Beyer M160s, AT-4050s, Josephson C42s, AT-4051s and Beyer MCE93s. All sound good and all sound different. You shoudl be able to get the AT-4051s or the Beyer MCE93s for less than $600 used. You would have to get lucky to get a pair of the other for that amount, but you could probably find them used for @$700.