Toolsprites shouldn't stand out, grey is nice and neutral, doesn't distract your eyes from the thing that counts 99% of the time, what's inside the window.
The point about coloured blobs is anything that reduces speed of recognition is daft. Why can't they be different colours AND different shapes? Position is obviously a good one, as long as it stays constant...
Also hidden GUIs (where you need to stop on an icon and wait for a tooltip to pop up, as seen on numerous badly designed websites) are stupid.
I'm sure everyone who wants pretty things can be distracted by a talking paperclip, then we can work on interesting stuff like zooming using scrollbars.