A Windows PC runs Microsoft Windows. After actually purchasing Windows XP Pro about 9 years ago, Microsoft never sent me a written apology and redeemed any cash back to myself for having to live with Windows 98SE, ME (remember that abomination) for about 2 years. I hate Windows 7 (don't have time for the learning curve as it tries and fails miserably to get that Mac OS-X feel but is harder to break than previous incarnations because MS just made it harder to look under the bonnet for its end users) and Vista so I am still working with XP Pro (which finally achieved some stability after service Pack 2 release), which again screwed up my computer up installing the SP2 for yet another clean install back around 2005. No more money will be wending its way back to MS. Lesson learned.

A Mac runs Mac OS-X (various releases) - generally fast and stable simply because Apple limit what hardware and software can be bolted on so generally remains sharp and responsive like a newly installed Windows OS. Apple use the same hardware commonly available on run of the mill and or high end Windows PCs so despite the slick and well designed overall effect, from a hardware perspective there is nothing special about the Apple Mac. Apple Mac not having BluRay support for example shows its detain for its customers who want their PCs as an entertainment hub. Apple probably think their customers wouldn't lower themselves to watch a HD movie on their entertainment system using a Mac when high end audio visual manufacturers such as Marantz and Krell are around.

A Linux Box runs various Linux operating systems such as SUSE (mostly freely available). You can get a reasonably decent PC for zero cash outlay by dumpster diving around the local refuse skip and installing Linux on the parts recovered such as the motherboard, processor, memory etc.

At the end of the day it doesn't really matter, its how fast your Broadband connection is (90% of the time, the other 9%, well you might as well get a proper games console). The free dumpster dive Linux box will have faster web page access and can probably even view BBC HD iPlayer content with a 50Mbit/s Cable connection compared to a $22,000 Mac (yes I priced up the highest spec Mac on their website) with a 256kb/s ADSL connection (which will struggle to play a low resolution Youtube video).

Current PC is a Intel 330 Atom processor, Ion motherboard, 2 Gig of RAM, 64Gig Flash boot drive and 500Gig content drive running XP Pro with BluRay drive, T-class Audio Amplifier, DVB-T card (pulled from another PC) etc. (yes it plays BluRay movies unlike the Apple Mac and is completely silent and idles @ around 25 Watts power so no 1000W power supply causing rolling power blackouts and can be powered by a Solar PV power supply setup come summer time, with the appropriate PSU design for automobile use)

I'm now currently considering a cost effective USB SDR Short Wave radio project setup such as this;

http://www.g8jcf.dyndns.org/