Hey st0r4gem4ster, welcome to MyCE
Usually American members tend to order at Rima and Supermediastore as said before.
If I remember correctly, copyright levies must be paid for CD-R in Canada (but not in the US), therefore it won't matter much.
As a European, I order a lot from eBay (one can find good deals for Verbies with free shipping), but Damrotech and Tomdax are also very popular in Germany.
I personally consider YUDEN000 T02 (Taiyo Yuden 8x DVD+R) and MCC 004 (Verbatim 16x DVD+R) to be the best DVD blank media around.
TYG02 (Taiyo Yuden 8x DVD-R), YUDEN000 T03 (Taiyo Yuden 16x DVD+R), TYG03 (Taiyo Yuden 16x DVD-R) and MCC 03RG20 (Verbatim 16x DVD-R) are good options, too. It's also recommended to burn two sets of the backup, on different media, so one won't have "all the eggs in one basket".
If you go for TY, make sure they're genuine, if you go for Verbies, make sure they are the MCC type (purple/blue or orange/blue packaging, not the "value series" blue/white ones)