Leopard contains *needed* fixes for Tiger
One of those fixes is Bluetooth A2DP support for the on-board Bluetooth hardware, which will finally allow Apple to support the use of wireless Bluetooth stereo headphones. We have mice, keyboards, cell phone, PDA support via Bluetooth, but not advanced Bluetooth protocols such as A2DP.
Support for A2DP is available from most (every?) manufacturer's Bluetooth USB "dongle" that can be used under OS X, so it is simply inexplicable why Apple doesn't provide the same support for its own built-in hardware. Apple updates other drivers "in the field", so why not Bluetooth?
There are other driver and operating system fixes that can be "backported" to Tiger, and should have been "backported" long ago -- and I say this as someone who has been writing/modifying device drivers and embedded code for various Unix, BSD, and Linux variants for over 20 years.
Come on, Apple. I don't need multiple virtual desktops, and I can buy my own virtualization tools (Parallels, for one). What I do need is fixes for device drivers, file systems, and networking protocols to allow me to continue to use my MacBook PRO with existing off-the-shelf 3rd party Bluetooth hardware until I can install Leopard later this year... in which you have promised A2DP.
\burt