Depending on the over all cosmetics, the 3210 head is worth about $200 - $225 street price (+ shipping if you sell online). If you were to try and sell it to guitarcenter.com, they'd probably only give you $75 - $125.
The Marsahall 4x10 1965b could fetch between $200 - $250. They have nice punch and are very portable. Seems there are people out there looking for them as they're a bit harder to get now-a-days.
That's just a rough guesstimate.
EDIT: You are welcome to throw it up on
http://gear-vault.com/classifieds if you like