Yes, we run an exchange server. How you would even ask how any computer would get an infected email to begin with makes me want to really question what you know about viruses.
Just because you run a mac doesnt mean you dont recieve infected e-mails. Granted, they may be targeting PC's but just because a mac user recieves the e-mail on a forward doesnt mean its no longer infected. you can still forward it on to a PC user, unknowing that it has a PC virus because your so careless enough to not run an antivirus program. Just because it reaches a Mac doesnt mean its now Virus free.
I really think your assuming me as a Mac hater. Im not. Mac's are awesome when it comes to CAD design programs, my problem is thst you think its such a superior OS over Windows. They both have their negatives and positives. for me, I prefer Windows for the gaming, its FAR superior in that regard. If I was into engineering apps and just surfing the web and checking e-mail, I'd go Mac. It's far superior to Windows in that regard.
bottom line, Mac isnt as superior to Windows as you think it to be. It just depends on what the user is wanting out of their OS. there is a reason most companies run Microsoft products, hence why there are so many viral attacks on the OS. Dont kid yourself into thinking if it was the other way around that Mac OS products wouldnt be just as vulnerable.
I could run the Amiga OS on a system and claim its even more secure than a Mac only because of the fact its not as widely used. I bet there are NO viruses that affect the Amiga OS.