Since I mostly climb trad style, I don't use quickdraws for leading outside of the gym. I use alpine quick draws (two biners joined by dyneema slings) which offer benefits of adjustable length, reduced rope drag, and most importantly reduced movement (which reduces the chance a piece of protection wanders out).
There are some downsides to this, however: two of them being that gates of biners on alpine draws are more likely to open (at least with non-wiregate biners), and without the stabilizers found on ordinary quickdraws, the biners are more likely to move around (meaning the gate gets reversed or, even worse, ends up horizontal and a fall will load the gate—the reason I don't use wiregates for alpine draws).
I've heard before that, because of the above, it makes sense to place a draw with a locking biner every so often when you're at a place where you have an extra second to do so (easy spot, maybe a ledge).
What's everyone think of this? Anyone do this? Is it really necessary? Do you use two locking biners, or just one where the rope goes through?