When a button is important, it's not iconized. Please remove the icon and just make the font bold, that is: Login.
Maybe the icon looks good on certain Windows version (not on XP) but again, the program does not look serious anymore. It's really depressing to see a great GUI spoiled.
Also: the session tabs should be relocated, either as the first row (below menu) or the last row, and its row should have a darked bgcolor since it's not a toolbar, it's a tabs bar. Now they look worse than IE 6 with tabs support added by the MSN Toolbar. I know I can move the tabs, but why not take care of these details before launching the final stable version to benefit everyone? :?
You may say these are tiny details, but it's remarkable how these can ruin a once admirable GUI. That's exactly the reason why I was always reluctant to check for updates: I was afraid this would happen.