They're something I need - often desperately, but I just can't get on with their user interfaces. They're all the same, just variations on the old folder view. If I wanted that, I'd be using Vista's library views or spending my time working with Mac OS X's Spotlight. Instead, I'm after something that will find contextual links between my various emails and documents, and help me find the most relevant file.
Blinkx comes close to doing what I want, but that final step is a gaping chasm, and "almost" is worse than "not at all". So at the moment I'm using an unholy mix of Lookout and Yahoo! Desktop Search. Two tools that together give me a semblance of what I'm after. But I'm considering dropping them both for Windows Desktop Search, thanks to PHLAT.
PHLAT is a new interface for Windows Desktop Search (enabling search through a user's own email, files, and viewed web pages). PHLAT lets you easily specify queries and filters, attempting to integrate search and browse in one intuitive interface. In addition, Phlat supports a unified tagging (labeling) scheme for organizing personal content across storage systems (files, email, etc.).
It's the closest I've seen to the UI I want - and it gives me the ability to add my own tag-based folksonomy to my files, providing me with my own metadata for my own files. Worth giving a spin, I think...