I update regularly.
For at least a month now, the updates below do not install

Packages skipped because of dependency problems:
ffmpeg-libs-0.8.10-1.fc16.x86_64 from rpmfusion-free-updates
firefox-11.0-1.fc16.x86_64 from updates
gstreamer-plugins-bad-free-0.10.22-2.fc16.2.x86_64 from updates
gstreamer-plugins-bad-free-extras-0.10.22-2.fc16.2.x86_64 from updates
libvpx-1.0.0-1.fc16.x86_64 from updates
xulrunner-11.0-3.fc16.x86_64 from updates

There is a missing dependency,libavcodec52-0.7.5-47.fc16.x86_64 requires libvpx.so.0()(64bit) : Success - empty transaction

I can check or uncheck any of these, none will download.

Anyone having the same problem?? Is there a workaround?

Have you tried using yum from the command line ?
I often find that the GUI update tool fails to update but command line yum works fine. Plus you get to see where the problem really is.

Plus, have you tried updating/installing libvpx first before running the main update ?

I almost always use yum, the quote above is yum output.

I never had this before, I wondered if anyone else is experiencing the same thing???

We have an option like --fix-missing in synaptic package manager. I dont know what s substituation for yum. Try this.
Or maybe you have to add some repo address to your lists.

I saw the same problem. However, I just downloaded the most most recent F16 builds of each of the problematic rpms: (I don't have gstreamer-plugins-bad-free-extras installed), then manually updated via the rpm command.