Some new features:

  • There are a lot of new stuff in memory management for Vista, for example: it can detect faulty memory address, and dont use it, so bad memory wont cause BSOD, the whole memory manager have been updated to reflect todays memory sizes, superfetch for faster program start and USB memory for cache....etc.

  • Transactional File System
  • Transactional Registry

  • always everybody forgets one of the biggest: DWM (not part of Aero, and not backported to XP)
  • every win app refreshed (maybe Paint not, but who knows)
  • new apps
  • new look and feel (Aero, not backported, with new backgrounds, new screensavers, new start menu, new windows switching etc)
  • new audio stack (per app volume control, low latency, "glitch free")
  • new network stack (IPv6, network awareness, network map, faster networking, IPsec, etc)
  • new shell with new control panel applets.

  • search throughout the system
  • new Driver Model
  • new Help system
  • new print spool (Metro)
  • new Error Reporting and Problem Solving stuff
  • new Image Based installer
  • a lot of new technology supported (for example EFI...and a lot more)

  • security features (new firewall, UAP or what its called, Defender built in, services has been changed a bit, sandboxing, etc)

  • later-> WinFS
  • WMP11
  • Ie7 -> will have some Vista only features

THESE FEATURES WERE VISTA ONLY!!!! not backported.
and here comes the backported features

  • sidebar
  • WinFX(Indigo, Avalon)
  • Ie7
so...as i see it, there is a lot more new here than just the backported stuff