If you run AutoCAD, you are doing so for professional purposes (nobody drops $4000+ on software unless they need it badly, or almost $1000 even for AutoCAD LT). Under no circumstances should you be upgrading anything AutoCAD relies on until you have official word from them that it works. Doing otherwise is risking what you are relying on to make money for you and your employer.
I don't know the specifics, but AutoCAD appears to work on Vista now, so clearly whatever issues there were were resolved. It could very well have been that there were bugs in the initial release of Vista that broke AutoCAD, and they decided to wait for Microsoft to correct them rather than working around them.
It wasn't like you couldn't still buy a computer with XP installed instead of Vista.
AutoCAD was the main reason that people called Vista out for incapatibility in the business sector to my knowledge. There were issues with Campaign Cartographer 3 which seemed to be resolved and somehow are now back on Windows 7. Like I said before, I had Vista for a year and I never had issues from it. The people now who are singing the priases of 7 seem to either have never tried Vista on a computer made for it, or had issues that weren't related to Vista (shitty sound cards and old software issues)
Likewise, I think Windows and the other companies should jump on these manufacturers because I worked at Fry's for a while and I remember that one of the biggest issues was Vista and people wanting XP. Computer users need to learn they can't hold the rest of us back because they don't want to progress. Some guy came in and bought a 4000 laptop and they had the audacity to get mad because there was no plug for his dial up modem and blamed the salesperson (he saw and touched it in real time).
The manufacturers were making XP machines, and when Vista came out, they literally just tossed Vista into it and shipped it with that "Made for Vista" sticker on it.
I could tell they weren't Vista computers by the specs.
I am running an HP with 2 gigs of ram and 1.6 gig dual core, things work great for me with just that. My friend is running a quad core and he says he never notice memory issues what so ever. That just goes to show a lot of it was a problem with specs.
@Karmentok: What about my issue with CC3 that was fixed in Vista and is back with 7? Every OS has issues, how long was XP out before Service Pack 2? No one seems to remember that. Service Pack 2 was 3 years later...that's 3 years of messed up issues XP had