I don't really have a choice. If I want to do what I'm saying - growing most or all of our produce - I've got to extend the growing season, and I need a place to stage it all. So a greenhouse is a must. I found plans for this one online, and it looks pretty good. I like the design with the clerestory windows up top. And it seems simple enough to build in one day (I know...famous last words.)
At about 80 s.f., this one's pretty small, but should be enough room for what I need. I'll build shelves on the south side to hold trays of seedlings, and will have a bench on the north side as a work area.