Judging by the pricing and upgrade decisions made by MS, and the absolutely huge surge of interest for Ubuntu, I'm guessing Win7 will have a tough time

There's no upgrade path from XP to 7
you have to buy a full priced copy of 7, and do a clean install
At the peak (trough?) of the recession, this seems bonkers, and I think the sheer cost is the driving force behind the interest in Linux

I must have seen half-a-dozen mainstream news sources comparing Win7 with Ubuntu in the last few days

Examples
http://www.guardian.co.uk/technology...indows7-review
http://www.washingtontimes.com/news/...ts-user-nerve/

I don't think 7 will flop as hard as vista, but it certainly won't gain much traction either, if these early signs of discontent continue