Fruit of all kinds (mainly sweet) berries,small fruit

I think you get a lot of fruit on blackcurrants for the space they take up if you like them. Im growing blueberries and dwarf apple trees in pots with strawberries around them but i must admit im a long way from making any jam. I think it takes time (years) untill you get plentyfull fruit. I have heard that gooseberries give pounds of fruit but ive had mine 2 years and fruit aint plentifull yet. I also think it depends where you live. I live in scotland and the thing growing best for me so far is blackcurrants. I will be intersted to hear what others say as i also want to grow plentifull fruit!

apple trees dont take up that much room. I have two fastigiate ones (grow straight up instead of spreading) that crop very well. My sister also has a small tree that has had 3 types grafted on to one root stock. This is called a family tree and you get 3 different types of apples on one tree.
I also have two blueberries in pots. Your local garden centre (if a good one) should be able to identify loads for you.

Strawberries are good value and if grown in upright strawberry planters take up less room.