Which version of X should I use?

[Hal Vaughan <hal@thresholddigital.com>]

I'm re-installing Debian on a system.

I tried this last month and ran into trouble with the video card (ATI Radeon 
All-In-Wonder).  It turns out the version of X in the current stable branch 
does not support my card well.  The previous version supported it and 4.2 
supports it.

So am I better off going into testing and getting X 4.2, or going backward to 
3.x (I can't remember the exact number of the last 3.x version)?

Also, what are the consequences of this when I'm installing other packages?  
Last time around I had some failures when I tried using apt-get to install 
some packages (I forgot the error message).  Does getting one (or a few) 
packages from testing cause problems with installing packages from stable 
later?

Thanks!

Hal