I start off many of my WB sessions by asking the participants to group together at their table and write a list of pros and cons about white-boarding. They do this on their team boards so it's an evil trick to get them up to the WB!

One of the cons I often see is "no remote White Boarding capabilities." And that's just not true. In fact - many of my customers now intentionally add in a blank whte or black slide in their PPT deck so they can "ad-hoc" a WB with a customer.

One great use for a WB is when you are reviewing / proposing an architecture with a customer. Often you need to make minor changes, add a box, reverse a data flow, relabel a component etc. The downside of using PPT of Visio is that it's difficult to do this dynamically. If you have a WB / drawing capability you can make those changes 'on-the-fly" and preevent the need for another sales call (and also misunderstandings and errors). Since no-one over the age of 12 can draw anything remotely artistic with a mouse I've been experimenting with tablets and drawing programs.  

My personal preference is the Bamboo Connect Pen & Tablet. It allows you to concurrently control your mouse/pointer with the standard mouse and the pen - and you can sketch/overwrite things on both PPT and the webcasts whiteboard. You can also modify Visio by allowing pen mods or dropping the diagram into a PPT deck.

For "start-with-a blank-page" type remote WB's then I'd look at the Papershow. It's a USB pen
that utilizes a special pad of lined paper. It's advantage is that you can see what you are writing and you can pre-draw in pencil (i.e cheat) on the pad before you draw it for real. It projects really well over a webcast. The downside is that you have to go through some complex hoops to do this for an existing PPT slide so it takes away much of the spontaneous aspect of your pitch.

Bottom Line - don't give up on dynamic drawing just because you're on a webcast. If nothing else - it will brighten up the presentation just because it is different!