I know, I am alone in the desktop thinking, but its the desktop I use other than on my laptops as I need win and mac on them for work reasons with specialist software. Linux is a great desktop for the right place, mastertrade ran it for 18 months until they were brought out, and needed to replace their pos stuff.
* What Linux currently CAN'T do
Work as an average Joe's desktop or gaming machine. Yes I know I'm generalising here. And yes I'm aware of WineX, CrossOver, KDE 3.x, Gnome 2.x, LGP, OpenOffice and all the other neat Desktop stuff that you can get for Linux. I use a lot of them myself. However I also know of some of the frustrations of getting average Joes to use Linux on the desktop in business locations.
If average user means games, then yes. but if average user means e-mail, web browsing , IRC, open office and multimedia , Movies, and MP3's then its Great, just get the right distro. Fedora Sux as a desktop, mandrake works, but is bloat ware Mepis Rocks, but I use CollegeLinux, but it needs some work, 2.6 will be a better release( I am on a preview now) but I admit, i dont use a lot of usb, just a pendrive and a camera, both work great. but we use macs for multimedia creation. so I dont use it that much. My favourite desktop is featherlinux, light fast and does all i need..... I have locked the desktop once (once since install that is) CTRL-ALT-Backspace to the rescue, I crashed his winXP laptop twice already today, Hold power button for 4 seconds to reset. It took us time to migrate our machines, but the move was worth it. we get most of our work done in Linux, we do circuits and Microcontroller programming in windows ( need the tools) make the manuals, and multimedia howtos on the Mac, and play games ... on the MAC .... Linux is use to get the bulk of daily work done. printing labels, dispatch records - most e-mail and the like. Linux is a good productivity desktop ... if its one you set up, and leave alone.
The main problems I see are in these areas:
1) Stability. Not stability of the OS. That's pretty rock solid. But stability of the apps. Linux X apps just crash too damn much. Particularly:
Mozilla/Firefox - mainly the Flash or Java plugin's fault, but plugins shouldn't crash the browser.
Hmmm ... Never had this happen.
Evolution 1.4 - damn LDAP backend is unstable as all hell. And there are a variety of other annoying bugs such as the NZDT time problem.
Still on 1.4 But thunderbird is my preferred mailer now anyway
GNOME - the panel, Nautilus, pretty much all of it crashes now and again.Rhythm box, xine, Totem, lots of others....
I don't use KDE but it probably suffers form similar issues.
Kde 3.2 is a pleasent surprise, its come a long way ... Sounds like you should try Sun's JDS 2. I think you might like it.
2) USB support. I've had soooo many issues getting USB devices to work reliably under Linux its not funny. For example:
MS Wireless Keyboard/Mice seem to get disconnected when X starts up. You have to unplug and plug them back in a few times to get them reinitialised.
HP OfficeJet Multi-function printers just "disappear" from CUPS and you have to shake a dead chicken over the Printer Config applet to get them to work again.
Solid state media reads just "lock up" after you've read the first couple of meg off the card.
Use these all the time, never had this issue
USB Cameras & scanners doing similar things.
As above, slackware seems to handle them fine
All in all I wouldn't trust Linux's USB sub-system as far as I could throw it.
3D graphics support is still very lacking and not overly stable. I've seen simple OpenGL screen savers lockup i810/i815 motherboards on a regular basis. The state of affairs is significantly better than it used to be. DRI did a lot to solve that. But nVidia is the only proprietary vendor that supports Linux to a significant degree and even their drives whilst pretty good still suffer from stability issues.
Real desktops don't need acceleration, .... OK I give you this one, its why I still use Xvesa as my normal choice for desktops.
One caveat is that this is all with 2.4 kernels. I've not used 2.6 much yet.
2.6 is a big improvement. In all the issue is is Linux the right desktop for your use. It can be. but its not always. I have Linux boxes that have not been touched for years. They do a simple job, are well hidden from the real world nastys and are left to do it and they do it well. Like all work issues. You need the right tools for the right job. If you do it right, and have the patience to work out how to get the best mileage, you can have a very pleasant Linux desktop experience. In fact as I typed this I opened cygwin, ran up a Linux window, and dealt with a dispatch issue, sorted out an error in an order form, and updated a product code. I do Linux on the desktop, and totally believe it has a place in my business. .. And its a much bigger place than windows has, but this is what works for me in a business, every business will get different mileage. but Linux IMHO can be a great desktop. The question is will it do all YOU need it to be in its current form. Thats much harder to answer.