This was one of my big reasons for getting the xoom. Whatever Verizon plan you get, you can share that with your other devices via mobile hotspots wifi or tethered. I use this all the time. There is no additional cost above the $20/35/55 a month for 1/3/5 GB of data on your plan.
I don't download DVD, and I have yet to exceed 2Gb. I am in the NYC metro area, and ATT is flogged, so I needed something reliable.
If you tether your laptop to your xoom, you need to go to wake it up one an hour by surfing to a new page, or the wifi mobile hotspots goes to sleep.
And yes it my laptop VPN works via the xoom mobile hotspot.