My biggest gripe with "modern OSes" is the dumbing down of the "media browsing" process. Eg:

1) N900, the default tracker settings index everything so you have crap like ringtones appearing in the video player and album art in the photo viewer.

2) Symbian, trying to select a ringtone from amongst a list 100's or 1000's of mp3s is an unpleasant experience

And you know what makes it worse? Both the N900 and Symbian phones auto create a set of default directories which includes things thing "videos", "music", "images" etc. I would expect the programs to look only in those directories (by default, with option to browse elsewhere), but no they still trawl through your whole filesystem and present a gigantic unwieldy list for you to crawl through.