Hi all, been a while but I am amongst you once more!

And yes, I'm on the scrounge for info!
I'm after getting myself set up with some VAG-COM software (suitable for a WinXP laptop) and a cable (USB to OBD2). Now being a good little forum-er, I have used Search and have come up with the guys at Ross Tech and had a look at what they offer. There seems, however, to be a number of versions of VAG-COM available and varying levels of funtionality, as well as something called VCDS. Basically the minimum I am after is to be able to read the fault codes and to access the Measuring Blocks live data, the latter being particularly important as I am hunting an intermittant fault and need to catch the swine in the act!
As far as I can understand VCDS does essentially what VAG-COM does but to get the full fat version of VCDS working I would need a Ross Tech cable at about $350. The alternative is VCDS-Lite with pretty much whatever USB-OBD2 cable I can get hold of via the 'Bay; much cheaper but much less capable.
Ultimately my questions for you guys are 1: Have I even vaguely got the right end of the stick here? and 2: Assuming I have, is the cheap option worth while or is it so limited in its abilities as to be a bit of a waste of time?
S.M.