I read a fair few reviews about running Linux on the desktop. One of the things that always springs to my attention is people moaning about hardware support. All things considered, I have an opinion about this.
My XP Installation at home does not work without significant time spent downloading (after I've installed a driver for the network card) drivers for sound/video/mainboard stuff. I have an ASUS mainboard, nothing fancy or special. It does not work natively with the drivers supplied with XP. It does, however, work just fine with Linux, specifically Ubuntu, but also SuSE. I run Ubuntu on a series of machines, including two Dell GX260's, a GX270, a Dell Server (the name of which escapes me) and various put together machines. I find fewer issues with drivers than I have had with XP. Don't even get me started on Vista. It's hardware support might be better, but you've got to have a *lot* more of everything to get it to work properly. Drivers for my printer - a HP 1022, were only released a little while ago for Vista. Ubuntu chatted away happily to said printer straight away.
As to usability, well I'm a little bit of a geek so I have no problems with it. I decided to test it on my girlfriend. Yes, I took my life in my own hands with this experiment. She loves it though. She likes all the games, can work the office software and everything else. She plugs in her Kensington USB key and it works fine. I'm about to add her to my wireless network with a Belkin wireless card - we'll see how that goes. But she has no problems working the machine. It's not a crappy machine either, an AMD 2200+ with lots of RAM and decent innards. Oh and an ASUS mainboard that XP required special drivers for.
When people talk about GNU/Linux being ready for the desktop, I'd like to point out that Windows isn't really ready for the desktop either. How many businesses etc are now saying No to the migration to Vista? Lots is the answer to that - check out on doggdot.us to see how many of the articles reflect the lack of interest in the upgrade path. I've been running Vista on a Dell GX270 and a Latitude D620 and so far, I'm a bit meh about the whole thing. Sure it's pretty and stuff. The low power gear is alright, but honestly? It's slower than XP and a *lot* slower than Ubuntu.
In terms of interoperability, I've got no trouble making my Windows machines talk to my Linux boxen or to my two Macs running OSX. There are lots of guides out there and they make it easy to get things working properly. I say "Bah!" to those who suggest Linux isn't ready for the desktop. I also reckon that in the future we'll see more of a move to an operating system that has open standards for longevity purposes.