I plant a few in each category, for variety mostly, but also because varieties like Early Girl will give me a nice tomato by the end of July, whereas if I only planted my favorites like Beefsteak, Brandywine or Stripers, I'd be waiting a long time for that first tomato.
You've got all the options in the world with as long a growing season as you have. The early's will still keep on going til frost, but will put out their biggest and best tomatoes early.
The majority of your heirlooms and huge-sized tomatoes are indeterminate. If you like to can tomatoes, plant a row of determinates to get one big batch of tomatoes and git 'er done. If you don't care to spread your canning/freezing endeavors out over the season, then there's nothing wrong with using indeterminates either. (Bear in mind, different tomatoes are best for different purposes). But if I was going to do 40 quarts of spaghetti sauce, I'd just want to get it over with myself.
Since you have a long growing season, I'd say plant what you like, what varieties you enjoy, then throw in a couple early season tomatoes just to get some on the table sooner.
Probably the only thing I ever did wrong with planting tomatoes was planting 30 heirloom slicers (3 different varieties, but all slicers!) and I was drowned in tomatoes that were great for fresh eating, but not all that great for canning. Other than that, I don't think you can go wrong!
) By next year I will have a good feel as to which onees I will concentrate on.
