Obviously I am joking around.
If you take away aero I am left with the following that are meaningful to me by contrast:
Fully patched and updated MCE 2005-
It has IE7 + WMP 11 like Vista, hardware sound acceleration, a media center I prefer, all my programs work, better gaming performance. MCE 2005 doesn't switch off my hard drives. Vista will do this even with a custom power profile, all I can do is increase the time it waits. MCE 2005 with the right services disabled seems quicker as well. Oh yes, and HDR+AA in Oblivion ftw
The UAC and a new ‘randomization’ layer, which slightly changes the memory configuration of every Vista machine to make it harder for co-ordinated attacks to affect scores of machines at the same time.
"PatchGuard" on the x64 versions of Vista.
An improved more stable audio stack. DX 10.
Easier network setup and better networking.
IMO the UAC needs to be seriously
tweaked in order to be tolerated by most folks.
I know there are more differences and I touched on what is meaningful to me, not all changes.
Sans aero and the UAC I have a hard time telling the difference between the two in practical use besides preferring the media center on MCE 2005 and having better gaming performance with full application compatibility on the same.
Vista is still on my machine and will be used for DX 10 games, otherwise I'll be running MCE 2005. If the first service pack for Vista impresses me I could change my mind.