Can I make a collider ignore another collider, but acknowledge the rest of the colliders?
Can I have collision groups?
You can use Physics.IgnoreCollision to ignore collisions between specific pairs of colliders. However, there is no direct way to form colliders into groups and ignore them all with one call. You need to go through all pairs of colliders that you don’t want to collide and call IgnoreCollision on them.
3.0 has layer based collision detection which might be a solution for you, when it gets released 
@andeee: hey, that works for me! thanks!
also, unity 3 makes me drool. I want to purchase, as soon as I have the cash!