I currently have Mac OS, Ubuntu(Linux) and RiscOS systems networked together. The G4 iMac is a very ergonomic machine, so is the MacBook. I am very impressed with Ubuntu which runs on an old PC I put together several years ago. At the moment nearly all the web development is carried out on the Ubuntu system. Whilst the iMac is great for web browsing, email, document preparation etc., I don't find it so good for web development. The iWeb software is useless for my purposes and so I use Nvu, gEdit, gFTP and Firefox on Ubuntu. The iMac is used to test the site on current versions of Firefox, Opera and Safari. As I don't have a Windows systems , and have no intention of getting one, then I cannot test my site against IE, so I hope it works. And if it doesn't I blame the software.
Mac OS, Ubuntu and Web Software
As much of the software I use is open source it tends to run on both Mac OS and Linux. If there is a restriction I will note it.
Risc OS Software
From time to time I still use my 10 year-old Risc PC that was made by Acorn. It was a great machine and networks wonderfully with the other systems I run. Practically all the original site was created using the following software. If you want to know more about Risc OS a good starting point is RISCOS.org and for news the Drobe Launch Pad. I still use RiscOS for drawing simple vector graphics as it still has better software than any other free software I have seen. It's also very quick to start and access information.