Recently, I install Fedora 7 and then attempted to install Adobe Acroread and Real Player. Both failed because they wer expecting earlier versions of the library.

I begin the wonder if the rate of change is too high. Keep in mind that Windows XP hasn't changed in years, but we seemed to get a new release of Linux every 6 months or so. Proprietary software just isn't keeping up with the change.

It's up to you how often you upgrade. You could install your previous version of Fedora to get Adobe Acroread and Real Player working again. The risk you run is the same as not applying patches to Win XP (which has had many changes - look at the problems service pack 2 caused), but it's your system and your decision.

Before upgrading your OS you should consider the impact on your productivity. Since you have a requirement for those applications you shouldn't upgrade without first finding out how to get them to run with Fedora 7 (maybe you can downgrade those libraries). Other people may need the updated functionality or security enhancements that the upgrade provides.

I don't think you can say that the upgrade cycle is too frequent unless you have no control over what you install on your system...

Multi-boot is your friend. Keep 5 or so installed and experiment with them in your free moments. Once you are happy with how something is working, just change the default in GRUB.
I keep all data on a separate drive, and simply mount it to each distro.

RealPlayer, Firefox and Adobe seem to link to old versions of linux libraries even in new releases so I don't think the problem is solely about the fast pace of Linux development. The solution is usually simple, just install the required libs (libstdc++5 or compat-libstdc++-33) using your distros package manager.

I don't consider patches to be major changes to the OS. Windows gets patches all the time and they are usually to fix one problem or another. It's not too much different than patches for a particular Linux release.

Windows has been around for eternity and only gets SP1 and SP2 updates. Frankly, it doesn't change much. Simiarly, commericial Linux distro doesn't change all that much either, so may be a lot of these distro should be considered the cutting edge. The only downside is that many of the reasons to upgrade is to get support on hardware that isn't working all that well at this time.

Paul