I won't post the link but I've just received an e-mail from Netflights advising me of a sale on Delta/KLM/Air France from now to 31 May 2011.

London to Orlando is shown as 'from £335'. I don't know just when that's available but I did find lots of dates with sub-£400 fares for easy 1 stop itineraries with good connections.

I don't usually fly on those airlines but this looks like a real bargain to me.