I think it needs to be a choice. It is actually easily selectable via a "tweaks" menu that can be added to your Safari 4...
I’d like to use Safari more, but now only do so on my Ipod Touch 32g. Reason: Bookmarks bar location. I’d rather use a side-bar, and with folders. Maybe I’m missing the process for how to use that option, but without it I’ll continue to use Firefox on my MacBook Pro. The speed and other features of Safari would, without that glitch, move me in that direction.