You can pretty much get a copy of any software you want in the market at this point. There are some pieces of software which I think are rediculously priced and some which I think should be bought original so that you recieve updates and support that you may need.
Rule of thumb in my opinion is that every coorporate establishment or business should be using all original software and I find it sad that there are a lot of companies that use copy versions of windows when they can easily afford purchasing original licenses. For some individuals they can justify buying a pirated versions of OS and I can understand that but for companies I find that to be an unacceptable practice.
And now there is going to be the release of Vista at the end of January with the different variations. I know there is going to be a pirated version out there asap and work arounds for the security, no matter how formmidable the security for a piece of software someone will always find a workaround or crack if they see a major benefit for them to do it or work on it.
There are few things I tend to get original since it is ciritical software for your system, and most other software is available for free:
Ofcourse there are some pieces of software which I tend to rediculously priced so I get it through other means. I think the only major one for me is Adobe Photoshop because of how expensive it is.