I have always wondered about this all the while not because I am unhappy with the applications currently bundled with Linux. But purely in a business point of view, this is a pertinent question. A major reason that businesses shy away from embracing Linux is because many of the software that they use do not have a Linux equivalent. And some of these software do play a dominant role in the market in their respective spheres.
I can think of a few software like Adobe Photoshop, FlashMX, Director, Quicken Financial software, Shockwave and Adobe Illustrator to name a few.
Now Novell - a big shot in the Linux distribution market - is running a survey to determine which applications the users feel is critical for their enterprises and would like them to be ported to Linux. So if you have any software in your wish list which run only on Windows at present, then this is the right time to visit their site and let yourselves be heard.