We have 4 players in one room, and a remote DM in another room 100 miles away.
The DM has 1 PC in his room, and we have two laptops, a microphone and a flat screen TV in our room.
The DM communicates via video skype with one laptop placed on a table near the centre of the room. He can't see all of us, but it doesn't seem to matter too much. We can all see him.
We use a server-based VTT (it's free - I don't know what it's called) and both rooms log onto it (the DM uses his PC, we use our second laptop). We have the laptop connected to the flat screen TV, so that the VTT is clear and visible to all.
We've used this approach about half a dozen times now, and it has worked successfully.
What we'd like to be able to do is have multiple skype video feeds, so that we could invite other ex-players who now live miles away. I haven't found a product that does this, though.