Since the switch to bi-monthly releases I've only upgraded once - and that was to the December 2004 refresh (The last one with a static D3DX library). I think I might well move to June now.
There were only two reasons why I didn't install the Feb/April (even though I have them on my machine):
1. I need a stable foundation to base F1CM on. If I do install June-05 I'll need to retain a way of rolling back if it all explodes [looksaround]
2. That whole static-to-dynamic move for D3DX. I won't labour the point as that's been covered (too much) already, but bottom line is it appears to have been "solved" sufficiently in June-05, such that I'm a little less worried about it causing problems.
With regards to my previous terrain post in this journal, one of the big things I want to look at is the UVATLAS tools in the newer SDK's. I think it might go a long way to solving an annoyance I have with trivial terrain texturing [grin]
In other news, I bought GTA: San Andreas for the PC the other day. Expect productivity to drop if it's anywhere near as good as people have said... [grin]