Robert Pickton would be the most 'prolific':
http://www.crimelibrary.com/serial_killers/predators/robert_pickton/11.html?sect=2 (they've laid 12 more charges against Pickton since that bio, bringing his total to 27 - there is little doubt he killed many more)
Clifford Olsen is another one:
http://www.crimelibrary.com/serial_killers/predators/olson/1.htmlBernardo & Homolka:
http://www.crimelibrary.com/serial_killers/notorious/bernardo/index_1.htmlAllan Legere:
http://en.wikipedia.org/wiki/Allan_LegereI'll have to look into this more. I would imagine I could add to the list, but the above are the most infamous.
Btw...they don't believe all the Edmonton murders are the work of a serial killer. Some have thought there may be 2...that's an even scarier prospect than one. There's been 7 or 8 found in the past 2 years that fit a pattern, so he is stepping up his campaign, so to speak.
And you know if those were university students disappearing, they'd have acted far quicker. :-(