I went ahead and tried out Flock. If you haven't already give it a try. Firefox with a theme and some extra features. It's geared for people that use the web alot and specifically blog,flickr, etc.
You can read a nice indeph review over at PaulStamatiou.
My thoughts are that the blog and del.icio.us integration is quite nice. On the otherhand I'm unsure if a new browser is necessary. I would much prefer it to be extensions/themes/plugins for the actual Firefox. I already use Foxylicious to download my del.icio.us bookmarks. I prefer this anyways as it's easy to have private and public bookmarks and I don't mind using the bookmarklet. The blogging tool would be nice to have in Firefox though.
Hopefully someone will make a nice blogging extension if they haven't already. I would definitely use it at work. Overall Flock is a really neat browser but just not worth changing to for me. I'll stick with Firefox and extensions.
I should note that I posted this via Flock