1. I normally recommend RedHat or Mandrake for people who are new to Linux. Both have their cons and pros. RedHat is in my opinion a better system than Mandrake in terms of stability, performance etc. Mandrake, on the other hand, might be a bit more user-friendly and comes with popular software like MP3 and movie players and so on. Even so, I would recommend (note this is my personal opinion - there is no Linux distro that is right for everyone) RedHat. The latest version is Fedora Core 1 and you can download the CDs for free from
http://fedora.redhat.com/.
2. Many of those programs cannot be directly used under Linux (especially MS Office...), but some are, and for others there are counterparts that do the same thing but differently.
- Opera: is available for Linux, although personally I'd recommend that you use the Mozilla version that comes with the distro.
- MS Office: That's not going to happen. However, there is OpenOffice.org that comes with most distros and does almost everything the MS Office can do and some other things. It can also read most MS Office file formats.
- Adobe Acrobat: is available for Linux, although there are free programs that comes with the distro that can also read PDF files.
- Graphics software: I don't deal much with such things, so I can't tell you any specifics. However, the GIMP (GNU Image Manipulation Program) comes with most distros, and many people uphold that it's better than Photoshop et. al.
- 3D Studio Max: I don't know honestly. However, there are other 3D modelling programs. Blender is one.
As for the others, someone else will have to answer since I have no idea.
3. There is an almost infinite amount of free software available for Linux - you can do almost anything that you want. As for games, that's not quite as common, but some manufacturers do port their games to Linux. Some of the later games that have been ported to Linux include Quake 3, Return to Caste Wolfenstein, Unreal Tournament 2003, Neverwinter Nights. They cost as much as they would for Windows. There might be more, but I do not know of them. There are also a great deal of free games that come with most distros, although they might not be the most advanced games ever made. =)
4. Almost all Windows file formats can be read by one program or another. And yes, you can access Windows file shares and shared printers, and you can also share files and printers with Linux computers.
5. It is possible to preserve your existing Windows installation, although it's not necessarily very easy. It's much, much easier to have both Windows and Linux if you reinstall Windows instead. If you go for that, install Windows first, and when you create the Windows partition, leave some unpartitioned space on the hard drive for Linux. Then install Linux. If you install Linux first and Windows after, Windows' installer will overwrite Linux's boot loader, which makes it impossible to boot Linux. Linux's installer, however, will configure its boot loader to boot both systems.
6. You should be aware that although mostly anything can be done in Linux, it is often done in a very different way from how you're probably used to do it. It's made worse by the fact that many interfaces in Linux are made to look similar to Windows' interfaces. That confuses many new users since some things look alike, but then they don't at all work alike. However, if you give Linux an honest chance, I do believe that you will come to like it.