Try to think in terms of keeping your sound as clean as possible. I've found this is what works for me :
guitar > wah > comp > dist > eq > modulation > delay >reverb
Wah sounds different when placed after the distortion, but I prefer this way becouse it sounds sharper to me. Compression will make wah less aggressive, and will give you hard picking sound and sustain prior to distortion, and it won't amplify its noise. I found the best tone-shaping abilities with eq after the dist, since I use a Boss Turbo Overdrive and it has very little bass and plenty mids. Fine tune it on amps controls since sometimes modulation or delay (especially slapback) amplifies the tone or adds highs. Modulation (chorus, flanger, phaser...) produces the most dramatic effect when placed after the distortion. Putting delay prior to dist is just crazy for me, since it means that you distort what is sometimes a mess of delayed sounds, which results in a lot of noise and rubbing of different frequencies as in distorted chords. Reverb is self explanatory, I guess, and you probbably have it on your amp anyway. BUT, dont hesitate to experiment, chorus prior to distortion sounds very interesting, I've used it on occasions. And thats just an example.