[thefultonhow]

I think that we need to differentiate between the different types of software available for computers and see whether it's available for Macs:

1. First-tier commercial software. This includes Office, Photoshop, Quicken, Dreamweaver, Roxio burning programs, and lots of other software that is most important to us on PCs. Usually there is a Mac equivalent to this software -- there certainly is in the case of all the examples I mentioned.
2. Second-tier commercial software. This stuff gets shelf space at CompUSA, but few people buy it. There is lots more of this available for the PC than for the Mac, but since people rarely need to use the stuff, it doesn't matter as much as the first-tier software. Incidentally, I don't have any of this on the computer in front of me, and maybe one or two programs like it on my home PC -- one of which is cross-platform.
3. Shareware, freeware, and open-source software. There is a huge shareware base for PCs, and not as big of one for Macs. So the advantage here is clearly in the PC court -- but personally, on the computer I'm on right now, I have only two freeware/shareware programs that don't have Mac versions -- Daemon-Tools and mIRC -- and both have alternatives of one kind or another on the Mac side. On the computer sitting next to it, I have utilities like nLite and PE Builder that would be useless on Macs anyway becaue they're PC-admin-oriented.
4. Security Programs. Lots more of these on the PC than on the Mac, but nobody writes viruses or spyware for the Mac, so they're not really necessary.
5. Games. The PC has a huge advantage here. End of story. If you are a gamer, MacOS is not the right OS for you.

So the Mac is at a slight disadvantage in a couple of these categories, and more of one in the Games category, but in the category that counts -- first-tier commercial -- there's really no difference. And in the other cagegories (besides games, of course), you can almost always find an alternative program that does the same thing and is available for the Mac.