Long and skinny, San Marzano tomatoes are a superior (if not the superior) paste tomato. This means they have been specifically cultivated to have a high ratio of tomato flesh as compared to juice and seeds, making it easy to can and preserve. This also gives us more actual tomato for turning into fantastic sauces.
San Marzanos also have a unique flavor. They are sweeter than your average garden tomato and less acidic.
Although the San Marzano variety can be grown anywhere that tomatoes can be grown, official San Marzano tomatoes must come from the region around San Marzano, Italy. To make sure the tomatoes you are buying are truly San Marzano tomatoes, check for the DOP designation on the label.
Can you make a good pizza without San Marzano tomatoes? Definitely. But San Marzanos are a class of their own, tomato-wise. You'll spend a little more for a can of these tomatoes, but I think it's worth it to taste the real thing.
What do you think? Are San Marzano tomatoes the only way to go, or not worth the hype?