Haha
There are three things GOGgers inexplicably hate:
1. Steam
2. Gays
3. Macs
It's no wonder this place has a reputation as a troll haven.

Piss poor example. Samsung hard drives? No fucking thank you. The monitor is obviously worse. Where's the motherboard too? Or couldn't you find the dual processor board? It's server hardware so it's not cheap. That would also increase the cost of the processors as they're socketed for the server board. The keyboard and muse aren't exactly up to much either.

He thinks it's a troll haven because, well, he's here isn't he?

Well, personnaly, I often work with Photoshop, Illustrator, and Flash or InDesign simultaneously. And, well... it's such a pain in the ass on a Windows PC! But it works as a charm on my iMac.
Don't know about Linux, though.
Artists/graphic designers are (for the majority of them) strange people. They love working on a computer, but they hate coding and generally don't give a f**** about building their own computer. They just want to have a nice computer that works well instantly when pulled out of the box.
They really work "visually", I mean by that that the ergonomy and design of their workspace is important.
As all those elements are hardly found with Windows PCs, maybe you can understand why most of them use Macs.
That said, I'm not an Apple fanboy, and I really don't think that Mac OSX is perfect, it's just that it may be the best choice for what I'm doing with a computer.

Even with the disclaimer in parenthesis this is still far too much of a glaring generalisation to leave alone. I can't say I've ever met anyone who uses computers regularly for any given purpose that doesn't prefer self-built machines. Even if they have someone else build it for them and/or want a hackintosh. And yes, that applies equally to artists too. It's more likely a cultural preference than professional.

Whats wrong with Adobe's products on Windows?

Nothing. Adobe's software has been practically identical on both platforms for over a decade. Equally having multiple programs running is simply a matter of having enough RAM and configuring the apps properly. Same as with a Mac.

Personally, I'm sick of working on my computer, I'd rather work with my computer. That's worth a bit of money, though I always found the Mac Pros overpriced anyway - mostly due to the fully buffered RAM, and buying RAM straight from Apple is pretty dumb.
But the fact that the OP chose a Harpertown CPU over a Nehalem shows that he's doesn't get it. I wouldn't want him building my computer.

This thread brings to light something I've noticed about Mac users/lovers. They can't take a joke! Heavy duty Windows fans can make jokes all day about MS or Windows. But say something that's only a little bit bad or funny about Apple or Macs, then all hell breaks loose.
Another thing I just don't understand is that many Mac users feel that they are anti-establishment. Yet they are fans of a company that uses some of the worst anti-consumer measures for their products.

Dude, you should see Linux fans...

But, from what I know, Linux doesn't take a piss on its user base the way Apple does.

+1
Very true and it's a myth upheld by Macphiles that this is not so. Adobe software works just as well in Windows. The only difference is font support - opening a work made on a Mac in Windows can cause shifting and text to appear wrong because PC and Mac fonts (except for OpenType fonts) tend to be slightly different with slightly different spacing. That's how the myth came into existence because nearly all original work was made on Macs so when a company decided to shift to much cheaper PCs (with the combined advantage of better network support, better software support, etc.) they discovered discrepancies between the Mac designs and the PC imported designs. However, work made on a PC will be perfect on its own.

Yes, but Linux is free and open source. If it works, and it mostly does, than there really is little to make fun of. Linux users do remind me of people who still loved DOS even after Win 98SE was released. Apple though acts like your only renting their stuff and that it's not really yours.

Which is why it's unfortunate that OpenType has yet to dominate the font market. It's the only realistic choice for working cross platform.

Way to resort to broad stereotypes, there. I've seen some pretty amusing parodies and ads poking fun at Macs and Mac users; Penny Arcade's take on the Switch ads ("Hi, I'm Raven, and I'm a Pretentious Asshole") comes to mind. But I consider the OPs picture trolling because (a) as pointed out earlier, his laundry list of parts on NewEgg doesn't approximate the typical sort hardware (from manufacturers like Dell) that the Mac Pro is intended to compete against, and (b) as I've mentioned, there are far more cutting and far more amusing ways of poking fun at Mac users than slapping together a bunch of screenshots.
I'm not singling you out, but it strikes me as odd that people still feel the need to boost their sense of self-importance by dumping on others just because they have the Apple logo on their startup screen instead of whatever the feel is the One True Way - but oh well, whatever floats your boat, I guess.