I've been buying third edition books since the 4E press release at GenCon last year.
I' haven't stopped, but I am getting picky. It would be nice to have a 'complete' collection, but it just seems financially un feasible considering the Pathfinder product line. I am a homebrewer and almost never use anything as written. Maybe eventually when prices start to plummet on the stuff thats expensive now (Return to the Temple of Elemental Evil, which eventually I'd love to run with the Pathfinder rules).
I love the modularity of third edition and the ease of modification and creation of races, sperlls, magic items and other whatnot. There are very few 4E books I want (PHB, PHB 2, MM, DMG, AV, MP, FRCS, FRPG), but when I do get them I will be finished with it and will move on to getting more OGL compliant material.