Sacha Chua has been sketch-blogging with Colors!, a homebrew drawing and sketching app for the Nintendo DS that can email finished images via WiFi (among other things planned).
I don't even use Firefox & Firebug anymore, the revised Web Inspector in Leopard has been incorporated in Coda and that does everything I need and more.
Since my Firefox has been starting to really get dog slow and I haven't bothered to find out why, I've bounced browsers to Safari again. But, I've yet to experience the same Firebug joy with the new Web Inspector as Jon Hicks has. Maybe I need to play with it some more.