I was browsing the William Orbit website as his new album Hello Waveforms is released next week.
Scrolling through the Timeline section, I found that there is a "Strange Cargo" image in Photoshop 5 which is revealed when you press Command+Option (or Ctrl+Alt if you must). It also mentions that for Photoshop 4 it is "Big Electric Cat" (Adrian Belew) and in Photoshop 3 it is "Taking Tiger Mountain By Strategy" (Brian Eno).
A quick web search turned up "Venus In Furs" (Velvet Underground) for Photoshop 6, and "Liquid Sky" (probably a Swordfish reference) for Photoshop 7. Photoshop CS has "Dark Matter" which could be a reference to the Porcupine Tree track. Photoshop CS2 has "Space Monkey" which could be a Patti Smith reference.
If you don't have all these versions of Photoshop, you can see all the spash screens here.