I eat a lot of heirloom tomatoes. They're $3/lb at the farmer's market. My two favorites are the Brandywine and Persimmon varieties. I also really like Sungold grape tomatoes and the chocolate plum ones. We've been eating a lot of caprese salad.
This article from the NYTimes has some great ways to prepare tomatoes:
http://www.nytimes.com/2007/08/22/di...tml?ref=dining
And Cooking Light this month had an entire article on heirlooms. This recipe:
Heirloom Tomato Salad with Herbs and Capers Recipe - Fruits - MyRecipes.com is definitely on my to-try list.
I really can't imagine eating any other kind of tomato in summer. I do eat BC Hothouse tomatoes in winter, but they're a lot more flavorful than other possible choices. Not as good as an heirloom, but I can't go 8 months without fresh tomatoes.