i wonder if yr friend got his arguments from
here
stick with the OS for now. if/when the 970 comes out, you should be able to argue speed.
give rendevous (sp?) props for easy networking
give airport props for 54mps wireless/802.11b integration
give firewire props for being faster/more reliable than USB 1.1/2
give powerbooks their due (DVD burner, 5 hour battery, 15.2" screen, 5 lbs.)
give iLife props for bringing digital media to the masses
give Final Cut Pro/DVD studio pro props for being at the top of their field.
praise OSX for reliability, ease of use, beauty, etc.
always remember:
apple doesn't manufacture the cache, RAM, processors, hard drives, etc. comparing a mac to a pc isn't the right way to go. go with what the company does. apple makes wonderful periph tech (see above), terrific software, and a drop-dead wonderful OS. they got stuck in a relationship with a bad developer (motorola), and if they should go with a certain chip later this year, indications are that benchmarks would be a wash.