10. The great urban outdoors. Now that I've made a great argument for culture and dining, let me switch tracks and recommend that you spend at least part of your time in Chicago recreating. One of the things that makes Chicago such a livable city is its parks, beaches and its all-around regard for the outdoors. Many of my Chicago friends won't take vacations in summer because they consider it so perfect here then (these are the folks you meet in the Caribbean in February). Hit the lakefront and rent bikes or skates, take a walk, watch birds (fall and spring are particularly good for migrating birds along the Lake Michigan flyway), swim or join a sand volleyball game at North Avenue Beach (the last two are summer only, of course). Even in winter the ice shard stacks along Lake Michigan make pretty scenery, provided you're well-bundled.
Elaine Glusac is the author of USA TODAY's Chicago City Guide