If you're just printing text, a lower brightness might be easier to read. You don't need the smoothest stuff for memos, but it can make for vivid photos. This matters if you're planning to print on both sides, or duplex printing. It is also stiffer - better for report covers, for example. Your printer won't deftly handle paper over a certain thickness, so check before stocking up.
Few things are more annoying than pages that jam up inside the printer.
In my experience, the lightest, cheapest stuff jams the most, and then mainly in laser printers. This doesn't matter much for memos, but you'll care for photos and possibly for some reports. It works in my laser, my copier, my multifunction fax machine and even in my inkjet for drafts. I'm going to put in frames. When possible, I buy my paper with as much recycled content as I can find.