If resale value is at all a consideration, go with the M3. Most of the $ you'll put into the 335 will immediately depreciate, and the pool of potential buyers will be substantially decreased (including most dealers, Carmax, etc.)
If you like modding your car, and you're going to track it until it dies then stick with the 335.
2011 BMW 335is Convertible
2011 Toyota Sienna Ltd AWD
2010 Lexus HS250h
2010 Honda Civic LX