Last I've seen, code folding has been requested from day 1. And I see requests / lamentations / mentions of it every time discussions about it crop up, without exception.
Personally, as shiny as the scroll-preview is, the fact that it doesn't show the structure of the entire document makes it almost worthless to me. As much as I hate visual studio, MetalScroll[1] was fantastic. You can see functions by shape, visually navigate the entire file at a glance (though I have good visual memory, so that may be easier for me), and it shows folds, breakpoints, changed lines, and selections. ST2 shows... about a screen in either direction.
I would like to second this sentiment. That feature has become a vital part of how I navigate code, especially for projects that I am looking at for the first time.
It's the only thing preventing me from using SublimeText 2.
SublimeText's minimap is not as feature rich as metal scroll, but its pretty useful in general as a nav tool. I often find myself wishing Chrome had a scrollable minimap.
The userecho page on Code Folding has a lot of votes, though there's some speculation that it'd be pretty difficult to do with the current implementation of the editor control.