I have a huge garden -- it's a quarter-circle in shape, with sides 35 feet long. Plus a seperate, 20x20 plot for space-hogs like squash.
What do I grow? Right now, nothing. It's 10 degrees out and a remnant of November's snow is still on the ground.
Come spring, though, I'll have the usual: mesclun, kale, chard, rhubarb, herbs, summer and winter squash, multiple tomato varieties, peppers, radish, tomatillos, onions, green beans, sugar snaps... Think I'll try sweet potatoes, too, and Ironman wants to grow cukes for pickles.
I'm jealous of your citrus trees! Enjoy gardening and be patient while you learn -- most people don't get a huge crop on their first try, but it does get easier. Read a lot. Check out the gardenweb forums. And Baker Creek Heirloom Seeds -- best seed company EVER.