CS6 will be good for years to come, I use very little of the new doodads they added over the last years anyway and am not in a business where I have to have the shiniest of all for competition (thankfully). Looking at how Nik and OnOne etc have advanced over the last couple years though, I'm sure there will be plenty other options for most photographers.
I'd actually be happy to sub in a year or two if it were a maintenance contract that leaves me with workable software once I decide I don't need more maintenance in the future. But I'd sure like my old software car to still take me to town occasionally. 'till then I'll upgrade LR, but nothing else.