How long ago
...was your last Linux install.
I've put Hardy and Jaunty on lots of systems, and generally it just works.
Almost every wireless card I've used (and I've got many rattling around in drawers at home) is recognized without need of a vendor supplied installation disk.
The last problem I had was the hacked Atheros chipset in my EeePC 701 with Hardy (fixed by a specific module from the community), but by the time Jaunty came along, it worked without problems.
What impressed me recently was when I took my mule system, and replaced the motherboard, which resulted in different processor, support chipsets, graphics adapter, memory, network - well pretty much everything besides the wireless card (it's a deskside system some distance from the core of the home network) and the media peripherals.
The existing Hardy install (yes Ubuntu 8.04 - two years old, but kept up to date) barely batted an eyelid. It recognized the onboard Nvidia graphics (it previously had an ATI AGP card), asked to install the correct driver for it, and came up as if nothing had changed. It just coped with the fact that the support chips changed from a VIA set to an Nvidia nForce set, or that the processor changed from an AMD Athlon XP to a Pentium Dual Core.
The last time I did this with Windows XP, I had so many problems, mainly because the Windows 'you've changed your machine, are you still entitled to run Windows' checks caused me to have to call Microsoft to re-authorize the retail version of XP (which is allowed to be moved between systems as much as you want). And the specific IDE drivers for the original motherboard refused to let me access the optical drive to enable me to load the correct ones from the driver CD packaged with the new motherboard to fix the problem.
I've not used Vista, but have built a Windows 7 system last Christmas. I was genuinely impressed by how easy it was to install, and it is clearly a step change from XP, The install I did was on pretty much generic hardware, so I would hope that it would be quite easy.
But comparing the installs of Linux and Windows is largely bogus, because almost nobody outside of the technical community actually installs Windows on any system. They buy it pre-installed, and just use it until it becomes so cluttered and slow that they discard the whole system. To somebody who has never installed a system, it will always be a traumatic operation to partition their disk and install a completely foreign OS with no experience of building systems. This probably explains many of the 'tried it, found it so difficult that I just switched back to Windows' type of comments.
Many of these people would find a second or third install so trivial compared to the first that they would change their view.