I recommend Centra. They replaced all the windows and doors in my house last year. They are one of the two main manufacturers of windows in BC. Their website is www.centrawindows.com
You should pay to get a inspection done regaurding the gov't grants available to homeowners for upgrades. The money you save can be spend on the HOT SP's here.
I used Oasis, I have 20 windows and 2 patio doors. Our house is a 70's style design with 4 - 5 large and odd sized windows. I choose a pretty basic white vinyl window without a lot of bells and whistles. Total cost was around 11k.
They had them all done in 2 days, I was very happy with the install, fit and finish.
Definitely look into having an energy audit done as you get back around $40 per window. If you do other improvements you get even more back, details here: