The time between Ico and Shadow of the Colossus was 4 years, but I remember reading an interview of Fumito Ueda (the director) in which he said that SotC was in development for 3 years and that he felt development needed to be streamlined in order to release games more quickly. SotC was released in Fall '05, so this Fall would be a great time for a release!
My Top 5:
Shadow of the Colossus, Metal Gear Solid 3, Shenmue, Skies of Arcadia, Chrono Trigger
My 2 nex-gen systems: PS3 
and Wii 
Prediction Aug '08: We see the PSP2 released fall '09. Graphically, it's basically the same as the current system. UMD drive ditched and replaced by 4-8gb on board flash memory. Other upgrades: 2nd analog nub, touchscreen, blutooth, motion sensor. Design: Flip-style or slider. Size: Think Iphone. Cost: $199. Will be profitable on day 1.
