Jup, do as much as possible local.

Effects and stuff can be (in normal case) made server-independent.
But it is not only up to effects, many other things can be reduced to only "triggers" to targets or handles, so that the rest is calculated local. The advantage is huge:
1. less traffic
2. less complicated game network control
3. less lag/jumps

One nice example is my game Starbattle I think, which was intended to send as few values as possible while keeping the gameplay smooth and filled with action using just trigger values, few vectors and handles.