Awhile back I bought a laser level to help with LOS for Dust Tactics. I also have found it very useful in Dust Warfare. Since obstructing terrain isn't done by true line of sight, but is done by drawing lines across the board between bases, the laser level comes in extremely handy to quickly check if there is any terrain between your unit and the opponent's.
Here's the laser level I have - Amazon lists it as $20, but I think I got it for around $15 at Home Depot. It's about the size of a computer mouse, and can draw a line across the battlefield.
You can also use it to provide lighting effects when your laser grenadiers shoot up a BBQ Squad! :-)