Tomato for us and in winter Leek and Potato.
Garden soup for me as well, most of the time, but I do like a thick leek and potato soup with home-made bread and Wensleydale cheese. The first time I used sweet peppers in a soup I was pleasantly surprised at the taste and use them quite a lot now.
Watercress in Spring as we always have excess growth ont he plants we sell that we need to keep in check.
A cold Gazpacho in Summer - and batches of tomato frozen for the Winter
Then an Autumn / Winter of Leek & Potato, French Onion and White Onion
Leek and potato for us plus a bit of all spice, in the autumn/winter, don`t tend to bother much with soup in the summer