Are precious metals involved (yellow gold, white gold, platinum)? 14k or 18k gold??
Are they quartz (battery powered) watches? That's a negative except for the prestige/luxury segment (Baume & Mercier, etc.). Quartz movements (except for prestige/luxury) have a definite lifespan, they die and the watch becomes a fishing weight.
Do they have the original boxes/papers? That's a negative if not.
As always, it's worth what somebody will pay for it, check against eBay or Amazon prices.
Otherwise search by brand, "Hamilton collectors forum", "Bulova collector forum" and see what each particular model is going for.
You can also search the better known auction houses to see what representative examples are going for.
http://www.antiquorum.com/home/http://www.ha.com/http://www.bonhams.com/departments/CAT-WAT/