fx send/return

I just picked up a mixer with send/return rcas and I really want to put them to good use

Question: What would you route through the fx send/return?

I've been thinking about a korg kp mini, but I want to see if theres something better to make use of this

I have a kaoss pad 3 and a loan of an efx1000 both do cool stuff but are getting a bit "dated" with all the cool effects you can assign in traktor.
Saying that both have their places and I definitely would use them from time to time

I was playing with the new Korg Quad in Dawsons a couple of weeks ago and loved it - thinking about getting one:

http://www.korg.co.uk/products/dance.../dj_kpquad.php

the kaoss pad quad looks VERY interesting