Multiwan with VLAN on a Veriton N270G / Linksys SLM2008

[Guldil]

Hi,

I'm trying to build a pfsense platform based on a Acer Veriton N270G (Atom Platform with Broadcom Gigabit controler). PFsense 2.0 boot on it.
For my VLAN i have a Linksys SLM 2008 (switch 8 ports Gigabit).
I have 2 WAN : one is classic ADSL Modem (With DHCP), the other one is a Routeur - Modem Netgear for Cable Operator (bridge Mode) working with DHCP & L2TP on WAN.

What is the best way ?

Create 3 VLAN (one for LAN, one for WAN1, one for WAN2) ?
Create only 2 VLAN for WAN and no VLAN for LAN ?

Thanks

Guldil