It depends on the music you're looking to play. If you're looking for a "clean" guitar sound, reverb/delay and chorus are nice and unobtrusive when used judiciously. A controllable overdrive is always good. The problem is finding an overdrive that doesn't compress your tone all to heck. The Barber Direct Drive is the best I've found, especially for the price.
I would HIGHLY suggest using an amp on stage as your monitor, and I'd mic it rather than DI it. A 1x12 combo will do a world of wonders.
I play a 50w Marshall through a 4x12. I really don't like reverb, I only use delay when I have to, I use the chorus only to add "shimmer." Here's my meager pedal arsenal.
