I routinely host games with exactly the type of mixed group you describe. Only new piece of hardware I purchased was a nice omni-directional mic (just search Newegg for a good one) which is placed in the middle of the gaming table (you might need a USB extension cable too). The webcam is set far enough back to include whoever is sitting at the table. The "physical" players really don't need headphones. We just talk in a normal tone of voice and are heard fine. The "remote" players do need headphones to prevent feedback, although we've had some players manage to position speakers just right to avoid even this small issue. We used to use Oovoo for video, but had constant stability problems. Since Skype has switched to free video conferencing we use that, and are having a much better experience all around. (Although I miss Oovoo's button which automatically stacks the vids in a bar to one side of the screen. That worked very well to quickly get the video out of the way of the gaming table.) I did have a spare TV monitor set up to receive a copy of the Virtual Tabletop (plus any other images I wanted to show the physical group) but since everybody has a notebook or tablet now we just use those. Okay, one of our GMs is a bit retro and insists on setting out physical battlemaps. We just move the webcam in a little closer for that and move things as per instruction. Oh, and all this on a crappy 3Mb DSL connection!
