The raised beds / square foot gardening is a great way to increase the productivity in a small area. A lot of work upfront, but one huge advantage is if you get too much rain in a short timeframe it has no problem draining. I've seen many old fashioned flat gardens where 1/2 of it drowned out. Most plants can't handle soil that is soaked for very long.

I have a large garden, but still use the raised beds becuase the logs hold the raised soil & the mulch in place. Definitely the way to go for maximum productivity.