Heh and here I will jump in
Linux is a better OS in general than Windows, but it is not as easy to use, and obviously not as well supported... For instance Ill pick out a few of your programs...
>I also use CAD programs such photoshop, autocad, sketchup, 3d studio, so I want to know is that programs are also for linux.
Photoshop... Not directly supported by any means, Photoshop 7 can be run under Wine. However anything newer wont be. What is availiable though is the Gimp, which is also availiable on Windows, completly free, and the only Image manipulation program that is capable to give Photoshop a run for its money that I have run across. It beats out everything else I have seen except Photoshop, and it definitly does give Photoshop a run for its money, though it is slightly behind, not much and the average user wont notice most of the time probably.
AutoCad. Another one I use, unfortunatly again no direct support that I am aware of. There are other Cad programs availiable, but I have not used any of them that I have felt to comfortable with, and I am still trying to get 3d in AutoCad down so I run it on a Windows box seperate from my Linux box. Older versions of Autocad will run under wine supposedly, but the newer stuff will not that I am aware of.
Sketchup- Not real sure what program this is so I am not gonna touch it.
3dStudio- Once again no direct support, and I dont think it can be gotten to run under wine, though I have never tried. However there are alternatives. I have heard a rumor XSI ported SoftImage over to Linux recently, though I havent checked on it. Also availiable, and I knwo this one works as it is native to linux I believe, is blender. Blender is a pretty decent program and what I am using currently, not quite as powerful as 3Ds or XSI but not to far off either, and definitly a decently respectable program.
Out of those, Gimp and Blender are also availiable to run on Windows to try out before trying Linux out.
Linux is truly a good OS, and is quite capable as a buisness OS with things like OpenOffice, and is starting to expand out in other directions. Not quite as good in those directions due to lack of software support, but not to bad either. I currently use Linux myself for 3d and Audio, and can do decent work in both of those. But this is not for everyone, I also spend more time and have more knowledge on the computer than most people and consider working with computers a hobby of mine. For some(Most?) people this is definitly not true and with the learning curve of picking up any new OS it might notbe the right choice.
Linux lack of support also shows up in other ways as well, especially for your work in limiting your graphics cards. Most NVidia cards are supported, I am not sure about Wildcat but I believe those are, but ATI cards are difficult to get support for, in fact most people advise going with an Nvidia card for that reason. Once again, capable but you need to be willing to put some work in it.
As an OS Linux is much more stable than I have ever seen ANY version of windows, the closest to it is actually Windows 2000, which I consider more stable than XP SP2 any day of the week, and still use it for my windows OS when I need to do AutoCad. But really Linux is even more stable than 2000 will ever be, if it is set up correctly, again that goes back to being willing to learn it and put effort into it. A distro like Lindows will be easy to run, but will not be nearly as secure or stable because of its policies(Like keeping you logged on as root, a very frowned upon security practice because it will allow anything to affect your entire system, this is a large problem in Windows for instance)