I use GoldenFrog's VyperVPN. It's one of the only ones I've found that lets you tunnel traffic from a router through a VPN instead of just one host.
I run openVPN on my QNAP NAS at home - I just VPN back to it when on public wifi; costs nothing !
I reccomened witopia $69 a year for full 256 bit encryption $39 for 128. You can choose to login from anywhere in the world and my speed and ping time stays about the same. Great service overall!
When I look at Witopia's web site, $39 a year does not give you SSL. You have to pay $60 or more to get SSL.
Agreed on VyprVPN. You can also run Hamachi seamlessly through VyperVPN. I used HotSpot VPN for six years until I switched to VyprVPN. It's not the cheapest, but it is the fastest and most robust that I've found.
Which VPN do you use on your QNAP NAS? I'd like to set up a VPN on my QNAP but I'm not sure how to go about doing this. Are there any instructions on the Web you followed?
Witopia is nice since it works with os x, windows, and devices. Although lately it doesn't seem to be working in some public places and the speed tests have decreased quite a bit from last year. Started looking around at other providers.