I use CS3 on Snow Leopard just fine for the most part.
There is a bug Adobe never addressed that involves saving files manipulated by plugins. Unfortunately it affects the SuperBlade Pro plugin I use all the time : /
Aside from that no problems.
As far as the mac vs pc cost here is the main idea:
Apple and Microsoft are two completely different business models. Apple makes money off of the hardware, MS makes money off of the software.
You can notice this just by looking at the Operating System costs. Windows 7 upgrades from vista are roughly $200, Apples is $30. Buying a new OS for 7 to get the full OS is almost $400, the full OS (non upgrade) for snow leopard is $129.
Now, many people talk about the "Apple Tax" but you have to realize there is also a "PC" tax in the form of needing to buy antivirus and antispyware (unless you want the free stuff), paying more for office programs (iWork is $79, MS Office is much more) or programs that do things like disk partitioning, automatic backup, etc.
It is true there are a lot of similar components but apple generally uses higher quality components. Not many laptops out there have LED screens or are made of aluminum with backlit keyboards. This is all part of the cost of a mac. Aluminum cases are more expensive then plastic cases. If you look at companies that use higher quality components such as high end sony laptops you will see that the price is about even.
Mac vs PC all comes down to how people want to spend their money and what uses they have for a computer. For gamers, Windows is a no brainer. For creative professionals, its usually a Mac. For everyone else, its usually personal preference.