Best way to connect a MacBook Pro to a projector
HDMI will provide a higher resolution. You don't need to use any sort of special 'Mac' or Apple produced cable for this -  DVI to HDMI cables are widely available and affordable from the Internet retailer of your choice. Just hook it up and you're good to go.

(N.B. while HDMI is capable of carrying Audio as well as Video, the DVI output on your MBP does not output sound. If you'd like to connect your MacBook to the projector or some other external audio device, you'll need a separate, but again, quite standard, audio cable to do so.)