Wendy--
Giordano's uses 6-in1's, which are excellent! But you can experiment with different brands of crushed or ground tomatoes, as well as whole canned plum tomatoes which you drain and crush by hand. Contadina sells cans of crushed Roma tomatoes, which are very good.
Personally, I always add sugar to my sauce (1 tsp. per 28-oz. can), but you have yo experiment to suit yourself.
The seasoning I like is called "pizza seasoning" from Cost Plus, but Del Alpe makes a good seaoning blend (available in grocery stores), and you can easily make your own with dried basil, oregano, fresh garlic, etc. Giordano's adds red pepper flakes for some heat.
Keep experimenting!