Being a steadfast Photoshop user, Fluid Mask from Vertus caught my eye today. This photoshop plug-in for Windows and Mac platforms offers to make life easier for creating cutouts in Photoshop.
The demonstration I watched showed the removal of sky from quite a complex image. It was very intuitive and easy to follow, with very good looking results.
The show offer for this product is £129 (which continues through to November 8th), after which the price tag is £149. For this price you get both Mac and PC versions, plus two licenses.
Check out Fluid Mask here.