Hey Vanquished did you D/L the 64 bit version? Sazar is saying that it's a native 64 bit app but I found this on a forum where someone had/has same problem as you.
http://forums.hexus.net/operating-systems-applications/138553-vista-64-bit-version-itunes.html
Odd thing is that on the iTunes page iTunes v7.7 it shows the download is same for both 32bit XP with SP2/Vista 32bit and the 64bit Vista. Hmmmm.
Seems that as of v7.6 of iTunes it will play nice with Vista 64. And you posted that you have v7.7.1
http://www.engadget.com/2008/01/15/apples-itunes-7-6-plays-nice-with-64-bit-vista/
This is direct from Apple.
http://support.apple.com/kb/HT1426
This is all I could fine that seems could have been an issue.
[edit]
Question, How are your video drivers? It could be a video thing.
Found this about Cover Flow being very slow and ForceWare drivers. But it's dated.
http://forums.macrumors.com/showthread.php?t=317186