Speaking as a current Windows developer
One of my clients is running SQL2002 and refuses to upgrade because he said "as a business man why should I spend money replacing something that been working perfectly for 10 years?" Yes, I told him it's no longer supported, but he says "I'll switch when it stops working". So, I have to keep an XP PC to support SQL2002 (Vista won't install it).
When I got another PC it came with Vista - that's when I discovered SQL2002 would not install. Moved all my development to the Vista PC EXCEPT the SQL2002 clients' apps.
New client uses SQL2005 - ah! that installed on Vista AND XP. Considered moving all my development projects back to XP since at least all my projects work there. Then, another client informs me he's moving to SQL2012. Woops - installs on Vista but it won't install on XP. There went that idea.
Spent many hours the past month purchasing/building up a new Laptop with dual boot XP and Vista so I can have all my work on one unit when I travel. Almost there.
Conclusion, XP still works just fine. Vista works fine for the tools I use. I make money working on projects for my clients. I do not make money on hours spent going through hoops to keep up with what the OS allows me to do or not to do. So I really don't see any Win 8 in my near future.
