I used to use cardstock, but it really soaks up the ink and now my printer refuses to take heavier stock paper. After a 20 minute stand in the paper aisle at Staples I got some help. I ended up buying photo paper for sturdier items (boxes, etc.) and glossy laser printer paper for everything else. I didn't think the laser paper would work in my inkjet, but the guy at Staples said it would and he was right!
I wish someone made an inkjet coated cardstock that would hold ink well and still be durable for us crafters!
I use the same approach Colleen uses with trying to get as much as I can on my 8.5" x 11" piece of paper. I don't have borderless printing so I always select Scale to Fit Media in my printer settings in PSE so that everything prints on the page.