Don't expect multi-touch this year in Mac OS X (or soon but we could always be surprised). In no way would Leopard depend on such a thing either.Will Apple be willing to announce that 100% of Leopard features will function on the currently available MB/MBP and iMacs? If they do, lots of people would buy today. Why wouldn't Apple be willing to announce this. They'd sell a lot more macs now.
If they don't, then my assumption is that the rumored new interface with multitouch/touchscreen? is heavily used by Leopard and I for one am going to WAIT.
Any thoughts?
I cannot think of any thing that won't work just fine on currently shipping Macs. The only edge case would be the system using Intel Integrated graphics ... those may not get the full acceleration of QuartzGL and related items but I would expect things to degrade nicely.
If I needed a system I would buy one now... If I could wait a little while I would see what happens after Intel releases the new chip-sets (a MacBook with the new chipset would have better integrated graphics, hence more future proof).
In fact Leopard will likely on average improved performance on existing hardware over Tiger.
The only unknown, that is hard for outsiders to answers, is how much new hardware is tied to Leopard... did Apple plan to not bring out hardware until Leopard or is 10.4.9 ready already or do they have a 10.4.9+ with added hardware support waiting in the wings.
I lean toward Apple not being tied to Leopard for the near term hardware updates.