Using rhythbox 0.9.5 on Ubuntu Dapper Drake.

It seems that ratings are restricted to be in the range 1 to 5 inclusive, yet unrated songs are shown as zero stars (which I at first thought meant really unpopular).

Steps to reproduced:
1. Find an unrated song (e.g. one recently imported)
2. Notice that on the main screen and track properties it appears to have zero out of five stars.

3. Find a song you don't like (which has an existing non-zero rating)
4. Try and set its rating to zero - you can't.

Suggestion:

Assuming ratings are meant to be in the range 1 to 5 (and not 0 to 5), could unrated songs be shown differently?

e.g. show five little question marks (and on the track properties, add the text on the right hand side saying "unrated")

i.e. Before:

***** (five stars)
****. (four stars)
***.. (three stars)
**... (two stars)
*.... (one star)
..... (unrated)

after:

***** (five stars)
****. (four stars)
***.. (three stars)
**... (two stars)
*.... (one star)
????? (unrated)

In these examples, "*" is the current big star, "." is the little star (or if bug 144368 is implemented dot), and "?" is a discrete small grey question mark.

The new icon should be smaller/less eye catching than the current big star.

NOTE: I suggest using five question marks as then the user can click on these to set the rating.  Other alternatives like using the text "Unrated" make setting the rating harder to handle.