Use windows 8 if it is what you know. I think there is a limit of 10 still for client (non-server) so if you are good with that then cool.
I use vista still on one of my servers because quite honestly it does the job quite fine and no point in upgrading it if it just dishes out files the way it is.
BT has a support forum bro, best to read up:
NAS: Dell 530 Q6600 8gb 4tb headless VHP
KID PC1: Mac Pro Dual nehalem - 6gb - GF120 - HP ZR30W
Browser: Dell 530 Q6600 4GB - Kingston 96gb -gt240- hp LP3065 IPS - 7ult
Tabs: IPAD 1,2,3 IPOD3,HTC flyer, Galaxy Tab - all rooted/jb
Couch1: Macbook Air/Macbook White
Couch2: Macbook Pro 17 2.66 Matte screen - 8GB - SSD
HTPC: Asus C2Q8300/X25-V - Geforce 430- 7ult - Antec MicroFusion 350