i already use both. my old imac is running osx and our pc is running xp. people will go on about how macs crash, but that's os9. osx doesn't crash. mine has -never- crashed in over a year. and i do some pretty funky stuff with it, digging around in the system, fiddling with things, messing with the terminal [the command line.] my copy of ie crashes.. but never the os

if this was just me it'd be one thing, but i've talked to -tons- of people, including i.t. people supporting hundreds of machines at businesses, and they all say the same thing. in fact, a lot of them are just plain ticked off at still having to support pc's as well. i think more than anything it's the inconsistencies.
which leads me to the commercials.. i've not seen tv ads since i don't watch much tv. i've read the net ads, and frankly i've -met- people just like the ones shown. therefore, it's hard for me to consider them hard to believe, even though i'm sure they're actors. however, i have to agree that in addition to their trademark ad style they need to run some ads with real hard muscle info. and i don't mean some inane teen saying "yer gettin a mac, dood!!" or a talking cow saying how good the dancers look.
don't get me wrong, i like xp. it's a good os - the best windows yet. frankly though, as i'm sure jt folden could tell you also, there are a lot of things i just find quicker and more straightforward about osx than xp. of course, they're both modern os's and you'd be hard pressed to actually find somebody familiar with xp who couldn't sit down at an osx machine and do just fine with no help.
also, paul.. when you say a g4 costs more than a comparable pc, what stats are you comparing? just curious