An update came seconds ago in Ubuntu Lucid (it's not yet in the repositories but should be available soon), stating that:
ght-themes (0.1.5.4) lucid; urgency=low
- correctly set the wm buttons on the left corner
[ James Schriver ]
* Fix dark menubar text OOo (LP: #532461).
I didn't even install the theme yet, instead I looked at the source code and it clearly states: