I still use CS3 on Win7. My next machine could easily be an iMac, but not sure when as my PC is working just fine and I don't foresee any more demanding software coming my way (CS3 and Office 2007 work just fine). So, theoretically I could keep it until Firefox version 362 says it needs better processor than my i7 860. ;)
Really, few days ago I was tempted to buy some CS6 for Mac that can still be found around the net, but as I had no clue when I would be getting that iMac, heck, when the times come, I may simply opt for a software switch pain and forget the Adobe. And this is not about money, it's about my choice, you (Adobe) do not shovel that thing down my throat just like that, and plus try to make me think how happy about how cheap is to be paying that perpetual $29.99/month fee. It reminds me on banks and that word that means "death contract" in French.