Most ppl nowadays have intel mini-pci adapters in their notebooks, most distros will pickup intel adapters out of the box, some of them would require you to download a couple of packages and that's all, intel wifi mini-pci cards are decent cards, and if you get a laptop with a non-Linux compatible card, then it's only 20-30 $ to get a decent linux suppported card and you can sell the one that came with your laptop for the same price so relally not that hard to get wifi running in Linux, I have got Linux running on My Thinkpad in 2 minutes, and the same goes to all laptops with intel cards, also Ralink have excellent Linux support as I hear from those who use them.
Desktop wifi cards are getting more support through time for example Linksys has drivers for their wifi cards, and other manfacturers too.
Graphics support needs some time, but as long as developers are not releasing games that will run on Linux nativley people will have a hard time with gaming on Linux, for example id makes games that run nativley on Linux, I never had an issue with such games, agood example would be wolfenstein return to castle (multiplayer), id released a Linux version of it, and since it uses open GL it was very simple to get it running on my laptop (using intel extreme graphics 2).
For those of you who are pissed that Linux is hard and want to stick to Windows, well bad news applications like windows applications, have a lot of developers who are being paid big to make their apps as much user friendly and fool-proof as possible. Once companies start to release aapplications for Linux andall the software available for windows is available for Linux of all flavoures then you can expect users to start migrating with the open source community likes that or not.
But as it's looking to me right now it will take alot of time for a Linux variant to hit the market in a commercial form that will make ppl want to adopt Linux as a main OS.
Well some might say there Linux commercial Linux distros out there, well I don't think they are doing a good job at it, nor they are priced right (i.e Linspire, SUSE not the open-suse). What a company needs to be sucessful in the OS world as a commercial version ? Well they need to secure themselves with software companies inorder for them to develope apps that are as good if not better than their windows counterparts, they will need alot of companies to secure a good bundle of softeware for them, once windows users see an OS that is as easy for them to use as Windows, has a good substitutes for the apps they are currently using, can be used by the geek and the non-geek then at that point they will say huh ! that doesn't look so bad maybe I ' ll give it a try since it costs much less than windows and it doesn't come with windows's side-effects.
As long as Linux distros and apps are being released by volunteers then don't expect much user friendliness and expect the learning slope to stay high.