Penang Beaches
Penang's beaches are not nearly the draw card they once were. Due to industrialization and heavy shipping traffic, the water is not very clean nor are the beaches all that scenic. The developed beaches lie along the western end of the north coast.
Penang's main beach sounds like the venue for a Star Trek convention: Batu Ferringhi. There are a number of resorts here, and depending on when you book and when you plan to stay, you may be able to get some very good deals. However, since Georgetown is at least 15 minutes away by car, staying at the beach puts you at some distance from the most interesting things to see on Penang.
If you really think you're going to want to spend a day at the beach during your stay in Penang, then you might want to consider staying at the Shangri-La Hotel in Georgetown. Its within easy walking distance of the old town sights, and guests at the in-town hotel enjoy full privileges and a free shuttle bus to Shangri-La's resort on Batu Ferringhi.