ODB-II/VAG diag tools?

[Stefan Hudson <hudson@mbay.net>]

Greetings...

In the last couple days, my "Check Engine" light has been coming on for
a while, usually after hitting standing water (we're having the first
rain storms of the year now).  I figure it's probably bad insultion on
a wire somewhere, but I really don't want to take it to the dealer to
find out which one... after they told me I needed to replace BOTH the
window regulator and motor ($800 or so), then it fixed itself when the
door got slammed a few days later, I don't trust them very much.

So, I've been looking into some of the available ODB-II or VWAG diag
tools lately.  The ones that are obvious choices (ie, cost less than
$1000) are "VAG-COM" (http://www.ross-tech.com/vag-com/index.html),
"VDS-Pro" from http://www.baumtools.com/ (pricing not online - bad
sign), and the open source ODBII project (http://www.opendiag.org) -
this is the cheapest, but I'm probably too lazy to build the interface,
so the $200 VAG-COM software is looking good. 

Anyone have any experience with these or other diag tools?  I'm not
much of a mechanic, but I can deal with electronics and software,
which seems to be the most important thing with cars these days...

Any info would be appreciated.

Thanks, Stefan