I use spotpower.net for my electricity. I find them to be a bit cheaper than Enmax (I'm on the variable rate, which seems to be about $0.01 cheaper per kWh, as well as having a lower admin fee when compared to Enmax). In fact, on each bill, it tells me how much I've saved over the Enmax RRO since I started ($110 since Oct 2010)
Further, their fixed rates seem to be lower as well. Here is a link that shows the differences between providers in Calgary -
http://www.theelectricityshop.net/compare/City.asp
I've been very happy with their services, so I thought I'd offer them up as an alternative to Enmax.