In the Aqua one (non metal), it looks like you should move the buttons down some. Not that hard:

Resize the window by 20 pixels or so (you can do this from the Inspector palette in IB).
Do a select all to grab all the items inside teh window, and then drag it down until there is a nice space from the titlebar and the top buttons. Then resize the window untill it is snug on the bottom of the status bar.

Also don't forget to change the Download.nib file also (so the download window is non metal if thats your fancy)

Thats what I did, and it really looks great.