I've been using Costco Kirkland glossy paper (letter size) with my Canon 9000-2 for a year or so, and have been very pleased with it.
So far, I've been using Plus-Glossy-2 as the media-type when making printer profiles, and then printing.
I recently installed an updated print-driver for the 9000-2 that included additional media-types:
* Luster
* Semi-gloss
* Pro Platinum
* Plus-Glossy-2-N
My speculation is that the media-type of Pro Platinum or Plus-Glossy-2-N might potentially result in better prints. I thought I'd check with people on this forum with more experience and expertise to see if that was or wasn't the case.