Using Ubuntu is a compromise in many ways. Although it's true that Linux supports more hardware than Windows XP (or especially Vista, at this point) does, much of the odd hardware on desktop systems isn't supported or is only supported partially. Many pieces of hardware that ARE supported require some setup to get running. This gets remarkably better with each release, but it will likely be true for the foreseeable future.
The capabilities of Ubuntu are also different than Windows XP or Vista. When a Windows game player/user buys a new computer, he researches whether Vista or XP better meets his needs and what software will work with it. There is a LOT of Win98 software which doesn't work well or at all in XP. The same is true for XP software in Vista. If this user absolutely needs XP to play a game or runs Win98 in a virtual machine in order to get that one piece of software to run, there's no way he'll buy an OS and go through the pain of installing it when he knows that OS won't meet his software needs.
So that means the very first thing we need to do, long before installing, is evaluate our needs in both hardware and software support. If you NEED to use the scanner you have which isn't on the supported hardware list, you're going to be disappointed and leave quickly. If you're married to a piece of software and won't learn or can't use another piece, you're going to immediately begin trying to shoehorn a piece of software into Ubuntu when the software was never meant to run on the OS. You'll be frustrated and leave soon, as well.
When we have a good understanding of what hardware and software we intend to use and whether it's supported or not, the installaion process often become trivial.
I'm going to say something that will sound a little silly when I write it, but which many people miss. Ubuntu is best at what it is set up to do. That means that using the default applications is easier and better supported than using some new and different one you heard about in the forum. Ubuntu works well with hardware which is recommended and supported out of the box.
Life gets even easier if you buy your system pre-installed on 100% supported hardware from vendors like System76 and Dell.
Right now, Ubuntu doesn't play Windows games well (without a ton of work). It doesn't automatically connect and configure itself to your company's Active Directory network. MS Office compatibility is 95%. Some (few) websites refuse to work well with Firefox. Some codecs and DRMed material will NEVER play. There are very few options for video chat in Ubuntu at this point. You begin to truly understand the need for open formats and hardware specifications when you move to Ubuntu. You will hate DRM.
Your workflow will have to change once you move to Ubuntu. You will have to learn some new programs and new ways of doing things. Some things will be easier and some will take twice as long.
What Ubuntu DOES offer is hassle-free work once you are set up on it. Your workflow can remain the same for years without having to worry about downtime, reboots, or malware. If you don't upgrade the next LTS version of Ubuntu, you can have three years of solid work under your belt and cry every time you have to maintain a Windows machine. If you like just getting work done and have a stable environment to do it in, Ubuntu is a joy.
Or you could get a Mac and hand your wallet over to Steve. That works for a lot of people, too. Because the hardware and almost all software come from Apple, everything works together well.