Recently, since the GAME buyout, all my games from Gameplay have packed AND been despatched on the Thursday, technically allowing games to arrive with customers on the Friday of release.
There's a neat little trick with Gameplay, if you're interested. You only pay P&P once each order, so if you're planning to buy several games, put them all through as one order and any postage will be charged only once (so if you have 10 games on order, a £4.99 Guaranteed Next Day charge is paid once, meaning that it'll cost you £0.49 per game).
Checked my account and its being picked today.