I used to keep a stack of wards handy, but I'd never place all of them in one sitting unless I was having a ward war with the enemy support.
Currently I use the sightstone (which can be treated as a gp/10 item of greater efficiency than the others, if you routinely place the wards) and keep a couple of pinks in a second slot for counterwarding. It's very rare that I need to grant more vision than this, but I would happily buy more if I needed to and my team wasn't willing to chip in to cover the briefly needed location. 3 wards can give cover of all the important locations around baron, jungle paths, or sight into the enemy base. Why do I need to carry an extra stack of sight wards most of the time?
The fact that I get 300 hp on top of a free ward dispenser is just gravy, really.
edit - though I think if your team's strategy is to do heavy roaming and pushing, as we saw in some of the latest tourney's matches, you can skip it, since most of your warding is going to be aggressive counterwarding anyway.