Gertrude,
You ask interesting questions, the nature of which really answers them.
Do you want a simple, hassle-free (well as close to as possible) life with your computer. If so, then your "insert CD, drink coffee" installation philosophy would strongly suggest that you stick with Windows.
Is there any Linux version (and that's the first problem, the versions) that come close to this? Not really although I tried Ubuntu & it's pretty close, but I've still got to faff around to get it configured to play internet radio.
If you have a PC and you use it for serious work, and you don't want to have to take time out to install etc then stick as you are. You mention ODBC connections, and again I would suggest you stick to Windows for now.
If you are the sort of person who enjoys understanding what is going on beneath the covers, then Linux is good as it is more transparent so you can see how it does things.
It is true that the software capabilities on Linux are getting very good now - OpenOffice is probably at the same level of "bug-free-ness" as MS office (hmmm?) and there are several other packages out there that do as well. If I were a small business and I needed a stable desktop AND (this is the crucial bit) I had a good guy around who understood this stuff (or failing that the neighbours 9-year old) then Linux desktops in my business could save me from the relative expense of MS software, plus offer me more security and give me some added plus points.
There are benefits to be had in Open Source software, I publish documents in PDF and I can do a good job for very little cost in Linux whereas the MS Soluion costs me dearly, but that is pretty niche.
The bottom line here is that it is up to you - if you want the easy life and don't mind paying, stick to Windows. As an individual it's a cost-effective way to go.
If you're using several PCs, then the trade off between support cost and cost of software licencing can move very quickly in favour of Linux.
Having sat carefully on the fence in all of the above, for me it comes to one thing. Like you, Gertrude, how much time does it take from sticking in the CD to having to work something out that would be automatic with Microsoft, and at the moment I still have to take time out from real work to make Linux work. So I pays me money and gives Bill another fillip