Eastern side will be no good. If distance is a factor, Grand Haven is much better than Saugatuck, IMO. Saugatuck is a cool town, not a great beach. GH has a lot of action, nice sandy beach, and lots of restaurants and such to check out.
If you want to go a little further, I think Ludington is one of the best in the state. But most along the West side should do you well, Holland, Muskegon (Hoffmaster), etc.