It shouldn't be spinning for 6 whole minutes. The cache shouldn't take that long to fill. Is this an actual timing, or are you just trying to say 'It takes a while'?
It's hard to answer why something doesn't happen in the Apple OS, because we didn't write it, but it does sound somewhat like your iPod is doing something abnormal.
Also, there is no official 60gb build. So, I have to ask: Are these things happening with an official build? Because any and ALL questions about unofficial builds should be in the thread where that build came from, and nowhere else.