If you hit the "back" sidebar (bottom left) you can see the waterfall as well of requests, sizes, etc...
Also, if you install the "web developer toolbar" extension for FF, there's a "document size" function that will also give you file counts and sizes -- it's often missing things like webfonts and media -- but it does tell you how well your gzip compression (if any) from the server is working by showing you both compressed and uncompressed size.