I still don't see Snow Leopard as a new operating system system, I see it as a Service Pack, that I paid $30 for. If this was a service pack they would be on SP6 by now with Puma 10.0 being SP1, Juguar 10.2 being SP2, Panther 10.3 being Sp3, Tiger 10.4 being SP4, Leopard 10.5 being SP6, and Snow Leopard 10.6 being SP6. The only real difference I see with Leopard is that it does boot up faster than Leopard did, talks with exchange (finally I can view the same calendar on both my Windows system and Mac), the dock has changed a little, and it actually let's me dismount drives without me arguing with the computer. Everything else pretty much looks like the same.
Some might argue that Windows 7 is a service pack as well. Well, it isn't, in my opinion. Especially if you're using the Professional or Ultimate. I currently have Windows 7 Ultimate Signature Edition installed and it is a completely different animal. XP mode is a good enough reason to get it, especially for those people that are hesitant on upgrading to 64 bit OS. No longer do you have to worry about if it is compatible to run earlier software. It's almost like Windows 95 when they had the 32 bit kernel and 16 bit kernel all in one OS.