Kellog's Breakfast and Persimmon are two of my favorites that I plant every year. Also, for a yellow tomato the Brandywine Yellow has been my favorite - great flavor and has been a better producer than the red (Suddath) and black varieties. My all time favorite for flavor is Cherokee Purple, though. For some reason the Brandywine Suddath has a fairly bland taste when grown in my soil, contrary to what most people experience.
Traditionally,I try to have about 15 varieties every year (all heirloom or open pollinated), with about 4 plants of each. I have had to cut back the past couple of years to about 30 plants due to less time available for the garden. There are 5-6 varieties I plant every year, and the rest are new ones I try.