The structure I would most like to nick from Chelsea and take home: Roger Platts' wooden summer house from The M&G Garden. Traditional, classic, and utterly beautiful.
Wouldn't you like to be sitting having tea right there?
And the craftsmanship was superb. This finally made my carpenter hubby understand the point of Chelsea. Carved from Sussex oak by 'a local craftsman' (who clearly wants to stay anonymous - don't know why, I'd be shouting it from the rooftops if I'd made this), it's held together with traditional oak pegs and perfect proportions.