Many times, the latest OS version is not the most stable (like Windows Vista before the release of 7). In this case, what do you choose? The latest version or the most stable?
This applies to any OS, not only Windows, even if I posted the topic in that thread.

I choose whatever fits my computers best...
Like Win2000 for all computers around 1996~2005
XP for computers around 2005~2009
7 for computers newer than 2009 or with 4GB RAM

If you're referring to new releases only, I always wait and see if there's any complaints/praises before trying a new OS.
I never use Vista as main OS on it's days, however Win7 would be good enough to be main OS for me.

The most stable version I could see is windows xp with Sp2 or Sp3 for desktops and I do not recommend windows Vista.

Now windows 7 runs like a champ.

I tend to go for the latest, which sometimes is the more stable. E.g. I jumped to Windows NT 3.0 when it was brand new though infinitely more stable than the 16 bit Windows/DOS alternative that was mature. I also went with Vista on day one (all the betas too) but XP was still more stable mostly due to driver unavailability. So, I'll keep going forward even if I loose some stability... sometimes.

I don't remember Windows NT 3.0 o.o

I'm a tech freak, so I tend to go for the newest, shiniest thing, despite any stability issues. So far, I haven't had any problems.

I guess I'm somewhat in between, but more towards the newer end of the spectrum. Meaning I wait till the bulk of the bugs are worked out before I take the leap.