The new icons have a serious contrast problem - there's very little difference between active/inactive states.
Additionally, they look like they were made for an app 10 years ago. Wouldn't something closer to Safari's current buttons fit into 10.5 better? I realize there are an enormous number of 10.4 users out there (probably far more than 10.5, at the moment) but that's the past at this point. Shouldn't OW be moving forward with more metallic-looking buttons?
If this is just something transitional between 5.7 and (the fabled) 6.0, that seems okay. My concern is that these will linger far past the point where they should. They just aren't slick - they look faded and dated. Not really what you want a first perception of OW to be. I mean, seriously....This is the best damn browser on any platform, as far as I'm concerned (and I've used the absolute hell out of them all.) Why shouldn't it look the part, too?