Hi there,
what about this idea:
put the selection tool for circle and rectangle together. instead of two buttons, make options to this new selection tool:
1.) option to select amount of edges. three to make a rectagnle, four to make a rectagle, five to make a pentagon, infinte to make a circle.... with the alt/crt or the shift-key, to make regular selections.
2.) option to make "star" with the same amount of edges (eg, a pentagram in case of five edges)
3.) option to make selections floating by default.
hope, i can help a bit to improve the gimp..
whistler