What do you think is a good zoom lens to replace the kit lens for a Canon 7D?

The kit lens is more than good enough for a novice, especially one who does not understand that saying you want a lens with a better aperture range, speed, and lighting is completely redundant. If you simply must throw some money around, the lens that would be good upgrade to your perfectly good kit lens would be the ef-s 17-55. It costs around $1100. Any other ef-s zooms do not have the increased aperture range you think you need.