1. Graphical Interface is now using GPU.
2. DX10.x
3. A strong Search functionality.
4. IIS7
5. Drivers in userspace instead of kernel.
6. Hotpatching without reboot ( SP1 )
7. UAC ( Almost no need for AV anymore )
8. Ability to run as limited user without trouble, being able to elevate to admin upon need.
9. ASLR (Address Space Layout Randomization).
10. DEP
11. Function Pointer Obfuscation
12. Windows Service Hardening
13. A MUCH better firewall
14. NX technologies at the Hardware Level
15. PatchGuard
16. File System and Registry Virtualization
17. Internet Explorer Protected Mode
18. NTFS junction points
19. BitLocker Drive Encryption