(1) Under Vista this looks like vista explorer. I think you would make money if you offered a Win XP mode to everyone annoyed by the new overly fancy Vista explorer look. Annoyance with the new Vista interface is your chance to get real rich!
(2) Give options to hide or move entries in the "desktop", or put drives on thier own tree without distracting and screen space consuming icons and tree levels above. Eg under Vista you have at least four icons and three levels of tree above c:\. Thats annoying.
(3) Think about the menu system. It's hugely complicated compared to Windows Explorer and really hard to find stuff. Even the toolbar is messy. One review I read said "I didn't like it much until i fully customized the toolbar". Only 2% of office users customize thier toolbar - so you need a very good default interface.
(4) If you want to be radical consider extending the filter into a file search. If you have a filter "...\myfile_version_*.dat" running then clicking on a button which adds a directory column on the left side and extends the results to subdirectories would be quite sexy.
For me, having upgraded to Vista I just want my old windows explorer back!
My favorite features on xplorer are:
(1) Having filters such as ...\*.log and navigating directories with this filter enabled.
(2) Having bookmarks.
Other than that I don't care much. I don't even bother with split views. Prefer a tree that syncs to a window and the split view complicated this.
How much will you sell the company for? I am interested
