I really only use free software. Outside of software development I don't really have any other software on my laptops. I have purchased tools and never pirate them. Is pirating more of a Windows user's thing?
No. I know many designer/Mac folk that have never paid for any Adobe software in their lives and they pride themselves on each CS update so they can play with new brushes in Photoshop. (Okay I'm being a bit sensationalist.. CS5 Photoshop does bring in some pretty nifty content aware features)
Not that I have any data to back that up, just my general impression.
Win 7 is from about £75 (home/student); Mac OS X 10.6 is from about £25.
With Windows you get all the upgrades free until the next major release. With Mac OS X you pay for point releases and that is the price we see here? I note that Amazon (UK) has OS X 10.5 priced at c.£110.
From Apple Computer's website, http://support.apple.com/kb/ht1338:
Reference releases; update vs. upgrade
Mac OS X v10.1, 10.2, 10.3, 10.4, 10.5 themselves are not downloadable updates, they are reference releases, also called upgrades. This means, for example, you can't upgrade from Mac OS X v10.3 to Mac OS X v10.5 via a downloadable installer. Reference releases are available from the Apple Store online, Apple Retail Stores, and Apple Authorized Distributors (AAD).