Canon has undertaken great efforts recently to enhance its flash system and catch up to Nikon’s standard. As of late 2011, many of the new camera bodies now feature a wireless master mode for the built-in popup flash (600D, 60D, 7D), and all speedlites have a wireless slave mode for E-TTL operation.
With the 580EX II, the 430EX II and the new models 320EX and 270EX II there are 4 models to choose from now (attached to the Rebel T1i camera in the photo above is a Canon ST-E2 wireless speedlite commander).
Canon Speedlite Information and Reviews
270EX II info page – entry-level model in Canon’s lineup
320EX review – photo-video hybrid flash with flash tube and LED light
430EX II review – the current mid-range flash
580EX II review – the flagship model from Canon