There are tower Macs,(not an iMacs) I have two at home, it called PowerMac G5.
I am not agree with ThE_MarD about Macs. You can do whatever you like and system still pretty stable. The MacOS based on FreeBSD, not Linux, so one can say it is pure UNIX.
I have to admit, I used Windows for a few years, I have to use it at work as customers does not want to switch to Macs or Linux. But I NEVER paid for any of MS product. I started to use Linux and I learn how to pay for the well done work, I pay to support the developers. I got Macs by chance and I do not really mind to pay for a good program, thought I can still have it through the warez websites. It is a good quality products.
And yes, I used to work on the G3 iMac, I installed Yellow Dog on it and it was fast
