I'm still going to have to stick with "PC vs. Mac vs. Linux" being the worst because there is no easy way to compare them.
With PS3 vs. X-Box 360 you can point out key differences that distinguish the two. PSN is free, but X-Box 360 has more game variety. While I'm sure someone will argue this, it's generally true.
But Mac vs. PC vs. Linux, anything can disprove anything you could try. Some people argue that "Mac is meant for more artistic types", but why? Photoshop may have originally come out on a mac, but has been on PC for ages. Plus there are tons of freeware photo editting tools for both systems, and it's VERY easy to find additional programs for Windows. The same goes for music. Some argue that PC's are cheaper for the same hardware. True, but then you need to take into account the easibility for a dumbass to collect, install, and/or customize their computer to get their hardware, plus how long will it last? And when you get into how long a computer last, that's individualized for EACH SPECIFIC PERSON, and then it's impossible to throw a blanket argument down such as "MACS SUCK" or "PCS SUCK". And that's only off the top of my head!
Linux is worse (to argue for or against), because of it's capability and customizability, yet requirement to work on it and know what you're doing. If you're looking for a pre-built computer then it's bad for you, if you're looking for MAXIMUM customizability no matter how long or how much work it takes then it's good for you, and if you're anywhere in-between then how can anyone (except yourself) say if it's good or bad?
All you can really say is which operating system YOU prefer or YOU recomend, not which is GOOD or BAD because it really depends on the person. It's impossible to win an OS fight because not only are most people ignorant of the other choices, they fail to see that it depends from person to person, need to need.
I use all 3, each for their own reasons and my own needs, so I've tried them all and none have stuck out as "AMAZING EVERYONE SHOULD USE THIS" or "TERRIBLE NO ONE SHOULD EVER USE THIS".
Except Vista. Vista sucks.
Kidding! =P