Latest version of Win (8.1) is pretty stable. I've not had a BSOD at all. If possible I would do a clean install so you don't have any old bits (hehe tech joke) laying around. I use start8 to get rid of the metro interface. 8.1 does allow you to boot straight to desktop. I upgraded 7 to 8 without any issue or data loss but did a clean install later just to get rid of any Win 7 cruft and also clear away loads of stuff I didn't use or need anymore. I like 8 but have never used metro except by accident!
If you don't have any issues with 7 it may be worth waiting for Win 9 (due April 2015) which sounds like it may have a native desktop only mode.
I would go for it then. Most of Win 8 problems are because of the metro/desktop differences which make it like a Frankenstein operating system. I've never used it with a touch screen so can't comment on that but I do like my wife's Nokia Win8 phone which is pretty similar. I have a Nokia 520 which I uses an iPod Touch substitute and really like that.
Metro fails to be an easy to handle UI, apple is much better than that. But they just started and 8.1 improved a lot of the 8 failures, i guess the ui will further improve in the next years.
There is a way to include the start button in win8. Just google it, it'll pop up somewhere. I can't say anything about gaming performance as I only have it on my laptop, but it seems to be a bit more resource efficient than win7.
I had the same problem. My solution (dunno if it works for you too)
-search for windows updates in the pc settings
-build a house, plant a tree and get kids in the meantime cause it takes a zillion hours
-repeat until no more updates are found
-go to store, download windows 8.1
-leave a note to your great-grandchildren to install and reboot cause it takes another millennium