I guess the common arguments are:
"Mac's are only good for graphic designers!" (which is not true at all, maybe 10 years ago I would accept that but nowadays I guess it's just a matter of personal taste)
"If you have a problem with your Mac it's very hard to find someone who knows what to do to fix it" (The problem is that I never had a Mac that crashed or that had a bug that I couldn't solve myself or send back to the store for a brand new one)
"Mac's only have one mouse button" (To this argument I prefer to be silent or just say CTRL+CLICK??? And that's not even necessary with the recent Mighty Mouse)
"Mac's don't have software" (WTF? what software is the Mac missing? humm, maybe 3d modeling and animation, however, install windows via bootcamp and BOOM, problem solved)
"Mac's are slow" (Geez, they must live in other century other than me because I work a lot faster in my eMac (1.25gh G4, 512 RAM, no GPU) than I worked in my PC, which had higher specs in all fields)
"Mac's are a trend" (Maybe, to some PC geeks who buy a Mac to be "cooler", however, they work for something other than FASHION ACESSORIES you know?!!
)
You know, this year I've been doing a Course in Multimedia and Graphic Design Techniques, we worked both in Mac and PC throughout the year (14 students, all unfamiliar with Mac OSX at first), and the only a$$hole who still prefers PC's to Mac's after working extensively in both systems thinks he's some kind of hacker and that real computer people prefer Windows because it's a "troubling" OS, and it's a challenge to keep it running decently, he somehow likes this "I got a problem, WHOO, let's solve it!".
I'm happy to say that in the last 3 years, I've converted more than 5 people to the Mac platform, Apple should give me a Mac Pro
eheh
I'm gonna throw up now