Then you should be set. Your picture quality should be better than upscaled dvd when playing blu ray on a 720p set. Blu ray movies vary a little bit in quality of encoding, so not all of them are going to blow you away playing on your tv, but most should be very good.
Sound quality of blu ray can be considerably better than dvd as well, but you need good equipment to take advantage of it.
By the way, you can get good quality HDMI cables for low prices at monoprice.com