You grow what you like to eat !! Seriously, I know people who grow stuff that they don't like to eat (broad beans spring to mind) just because they are fairly easy to grow well - what's the point if you're only gonna throw it on the compost heap?
If you have limited space then you might want to skip veg that is cheap to buy - like onionspotatoes and carrots and concentrate on things that are best fresh - salad leaves are a perfect example, or that cost a bit more in the shops.
It realli is entirely up to you and your stomach!
