Music Producing: Mac Or Pc? Logic Or Cubase?, dilemma between bying a mac or pc Options

[suite156]

hi,

I bougt my first mac (Ibook G4) 2 weeks ago. I really love the OS. Now I am thinking about bying a desktop computer (powermac) for proffesional purpose. I'm a musician and I'd like to make pre-productions on a computer. I have been working with cubase sx on a pc so far, but my pc is no longer powerfull to serve my purposes.
If I would switch to mac, I would have to use logic (as cubase isn't really working well on mac) and buy all the software I already have on my pc. I went to the music shop who has 15 years experience in studio en audio software. He deals bought mac & pc. His answer was clear: if you buy a powermac, you pay double the price than for a pc, which will do the same job perfectly. the only difference is the OS. AND, you pay 3000 Euro, for a machine who has only 512Mb!
I respect his opinion, but I keep looking for different opinions. I want to do a serious invesment and I wonder If I should buy a mac or pc.
I use it for recording audio (not more than 8 tracks) and combinen it with midi

Can anyone help me out?
thx

fanatics & radicals, please spare me your comment. only inteliggent computer users.
fanaticism leads to aggresion.
Respecting each other choices is the better way, that's my opinion.