VPN Solution: You opinion needed!

I have two main offices and a handful of branch office as well as a handful of roaming laptop users and I'm looking for a VPN solution.  Each office has one or more windows servers (2008 and 2003) so I was thinking I could use RRAS.  I am currently working on setting this up but I'm not really excited about have windows work as a router, so the RRAS solution would have to be VPN only I think - which I am currently having trouble setting up.  I've also thought about throwing a linux box at each location and running either m0n0wall or pfsense.  Previously, we used Linksys RV042s and they dropped the VPN too often and over heated.  Im also trying to stay away from the probably very robust, but quite expensive hardware solutions like juniper, etc.  That said, at one of the main office locations I have a Zywall 70 which I haven't had to reboot in over 2 years, and it appears to support VPN, so I could use that as one of the endpoints.

Option 1:Windows RRAS
Option 2:Monowall/pfsense
Option 3:Zywall 70 and options 1 or 2
Option 4:other suggestions?

My preference is an IPSEC solution but again, I have an open mind.

Thanks in advance for your expertise