I've got to address some of your points because they're patently incorrect.
In 2006, there were two mac viruses "in the wild". There has been less than a handful since then. Viruses on macs are simply not something that Mac users need to be concerned about. The same with spyware and security as a whole on a Mac is far tighter. Yes, there was the recent hacker who supposedly hacked into OS X within 10 seconds. Well, it was actually a Safari exploit that required visiting a particular website. Read more into that story and you'll soon read it was actually a load of rubbish. (The guy typed in the URL to a previously prepared server he'd spent hours setting up before the competition).
Which is why there are numerous antiviruses out there for the mac, and Apple recommend you have one for your mac? There are plenty of viruses and malware out there for a mac. And no, the main reason there are less viruses out there for macs is due to the proportion of them in relation to Windows machines. If you want to cause as much damage/make as much money as possible, do you 1) make a virus for a platform that has less that 20% share in the market, or do you 2) make one for one that has an 80% share?...
"Then you need to realise macs do get viruses, crash, need upgrading, can slow down, have problems, to a very similar extent to windows PC's." is absolute rubbish. Macs do crash, there's no denying that. All computer systems crash (yes, Linux does too). Macs do not get viruses, need upgrading nor have problems anywhere close to "a very similar extent" to windows. That is simply untrue.
Take upgrading - the ability to upgrade any Mac (excepting the Pro and their servers) beyond memory and hard drive upgrades is simply not an option. Apple Macs have a far, far longer shelf life than their PC equivalents. You can run - and it will run happily too - the latest version of OS X on a 867Mhz G4 Mac, of which a model was available in 2002.
This is one of the claimes that I was referring to in the post you quoted. With the creation of XP (and especially SP2 or it) the stability issue went out the window. Even more so when vist came about, I have two machines running vista and in over 2 years (in fact since the Beta version). I have not had a single crash, I have had the occasional program crash yes, generally because of Adobe flash, but nothing related to the vista core itself. Stability issues are really a non issue with both of todays windows and mac OS's, bot crash so rarely there is no argument any more.
As for updating, macs do it quite regularly, in most mac users don't ralise because they are done more "behind the scenes" than windows ones, to the point a lot of security experts get a bit cheesed off with Apple, as most of the time they are not told what these security updates actually cover.
As for hardware upgrading, they have a longer shelf life because they are upgraded less, is that supposed to be a positive? Yes that means your 3 year old mac is not going to be as out of date against other macs, but it will still have the same performance as a 3 year old mac, and be more out of date compared to a PC. If upgrading only affected the OS then you would have an argument there, but it doesn't. It affects all sorts of things, from file opening times, processing times and encoding/compressing times to name a few. A faster processor/more ram will always make something faster, and this is needed as files get bigger, and processes get more intensive every year. (incidently this is another prime example of an argument mac fanatics come out with, and what I was alluding to with mythical hardware). Upgrading is not a requirement for windows PC's either, and generally most windows PC's won't be upgraded.
I've never, ever heard the "Macs start instantly" claim. Where did you find this claim? I don't really know how long my macbook takes to boot up, I never reboot it.
Read the link for starters. It's also one of the main arguments mac fanatics come up with regularly. And as for rebooting, I very rarely do mine either, and once ordinary people are shown the sleep/hibernate modes in windows PC they rarely do either.
Photoshop 1.0 was written exclusively for the Mac. It's never been "ported (with a couple of problems) to OS X. That's a load of rubbish. The first version of Photoshop for Windows was 2.5. And I can't find a single article on how Lightroom was ported from Windows to OS X either. By all means enlighten me. Software like this isn't "ported". How is Vista in any way a better OS for photo editing? What could I do in Vista to my photos that I couldn't with OS X?
See my other post about this, I wasn't talking about the old versions, I was talking about the versions that are used NOW. As for porting, most of the background code will be written for one machine, then altered to work on other platforms. This way you don't have two entirely different teams working on the same project at the same time, it saves time and money. The only issue with it is that sometimes it can be difficult for certain parts of the program to work as well on the ported as the original platform, without rewriting the entire code base.
As a whole, Macs are used by the creative industry because it's a more reliable platform that simply gets out of the way and lets users get on with their job. "Better" is personal. I've been a Mac user for about 4 years now. It is a "better" system for me. At the end of the day, I can get more work done with OS X than I can with Windows or Linux and I'm more confident in Apple hardware and software than I am with Windows and a machine from a PC manufacturer. That's simply going on my personal experience.
Possibly true in the past but again, not now, so with that in mind there are two reasons I can think for companies to keep using macs, 1), you don't need to retrain people in your organisation to use another OS and 2) you don't need to rebuy/find software/hardware to go with your newly bought machine. For new users these constraints aren't there, and so the culture part comes in.
I'm perfectly fine with you saying you can use OSX faster, but as you said it's personal, doesn't mean others can. Which is what my original post was alluding to. It's a personal thing, get rid of the stupid marketing speal round both OS's and just think about which OS is more intuitive for you. Don't buy into the hype.
I hate debates like this, as they go through exactly the same points over and over. The first paragraph comes back to the end of this post: Most of the supposed benefits touted by mac users are either older than time or just plain wrong, with the rest being personal opinion (where I have no problem).
So yeah, to the OP, just have a play around with both OS's and see which one you prefer, forget about the stability and "facts" touted around by both sides and just see which one you enjoy using more (if you have the extra money, as essentially you are paying an extra few hundred pounds for the OS user interface).
Actually, only a few days after it was posted to the Apple site.
Macs ARE more secure than PCs due to being sat on top of unix. It is possible to write a virus that will infect Macs but as yet the only problems have been TROJAN attacks where someone downloads a hooky piece of software and installs it. The main reason AT THE MOMENT for installing anti virus software is to protect Windows users by passing them on BUT the time will come when viruses do start to appear on the Mac. I would not be surprised though if Apple include a virus protection program as part of MacOS within a year or so. 
