I have to laugh at quite a few of the posts made in this thread.
First of all, the version number. Who here hasn't learnt already that version numbering is pretty arbitrary everywhere? Some developers use it to show that they've reached a certain milestone, others never get to version 1 because they kind of see that as reaching perfection, others use it partly to show when a batch of security patches have been released, the list of different uses goes on. The only silly thing about the version number is, if it's true, that MS didn't put it up to 7.0 because of (potential?) compatibility issues. Personally I think Win7 is v6.1 because it is a patched-up version of Vista
Absolutely it's a patched up Vista! So why didn't they just release it as Windows 6.1? Of course the naming is arbitrary, I just thought it was dumb/weird of them to make the fundamental marketing shift from the year-based release names they've been using since Windows 95, back to number-based release names like Windows 3.1, and not have internal and external version numbers match.
however the OP's comment about it being "barely different" - I bet 9 out of 10 people who upgraded from Vista (usually because of performance issues) to it would disagree with you. There's an enormous performance difference.
I don't doubt that there's a tremendous performance difference, not one bit. But will you agree that 7 isn't substantively different from Vista
apart from the critical bug/performance fixes? The Vista-to-7 transition seems much more like the 95-to-98 transition (or 2000-to-XP transition) rather than the 3.1-to-95 transition (or even XP-to-Vista transition). That is to say, under-the-hood improvements and tweaks rather than a fundamentally changed user interaction experience.
EDIT: A reference point for my comments in this thread:
Table of Windows versions. Note the internal version in the 4th column matches the external version until Windows 95.