I don't tend to plant annuals in the garden because I constantly run out of space experimenting with perennials that do well in Calgary. It took me years of gardening before I finally figured this out:
Got a spot in the garden that is seen from many viewpoints and needs to be spectacular all season long? Add a pot. Smack dab IN the garden. And experiment with fun and unusual annuals as much as you like while adding impact to the garden at the same time. Or, like me, stick with easy, cheap, tried and true for your pots so that you can have your fun with your perennials.
(Above: New Zealand flax, petunias and allysum in the pot. I know, no big whoop, right? But don't they look great against the perennial artemesia in the background?)