Jimmac has designed two alternative Blender Icon Themes based on Freedesktop.org's Tango Style Guidelines. The result is a refreshed, more modern look that many people seem to like, but it also raises a number of new questions.
*EDIT: You can find a Windows build with the new buttons here.
I've been occasionally working on a blender icon theme that follows the Tango Style Guideline. Not that Blender actually follows any interface guidelines on any of the platforms it runs, I just felt the default icons are somewhat 1990. I don't have complete coverage yet, but the most exposed icons are themed.
[...]Where these don't work so well is the button context header. The lower opacity makes them a bit unclear. I'd prefer the current button context was highlighted differently than making the other contexts semi-opaque.
If you read the thread on BlenderArtists, the most frequent request is to allow for a 'drop-in' icon file that allows everyone to choose their own icon theme. This makes a lot of sense to me; many people like the bright and colored look but others would choose for a more subdued and simplified set of icons.
In the comments, there is also a mention of a GUI redesign for Blender 2.5. While I haven't been able to confirm this yet, it did get me thinking about GUI consistency: does it make sense to redesign only a part of the GUI (i.e. the icons) without looking at the whole? Even if you think the current icons are outdated, they are an integral part of the entire GUI design and look-and-feel of Blender. Can you redesign one without the other, or would that lead to a broken, inconsistent result? I'd like to hear what interaction designers have to say about this.
Anyway, regardless of how wether you like Jimmac's theme or not, I hope you do agree with me on one point: instead of complaining about something, he simply put in some work and posted the result. I think that there are way too many people who talk the talk but don't walk the walk and they should take an example to Jimmac's approach.
To use the theme, you'll have to follow his instructions and recompile Blender. Maybe someone can drop a compiled version on Graphicall.org for the rest of us to play with?