I agree with the above, apart from wah. I hate wah on guitar (apart from RATM - Bulls On Parade).
I play guitar and bass in equal amounts and after years of buying pedals, always come back to the same handful of effects. My current board is:-
Ernie Ball volume pedal
Proco Rat (modded)
Boss BF2 Flanger
MXR Carbon Copy delay (long spacey delays)
Boss DD3 delay (set for short slap back delay for fattening the sound out, useful for the lone guitarist)
Hardwire Reverb
Planet Waves tuner
I try more 'out there' effects every so often but they never last long. Personally, I'd got for flange over chorus. If set subtly, you can get a chorus type sound out of the flanger and you've the option of turning the dials up for interesting noises.
Boost is also a good idea. I don't have one as I can't do solos. A volume pedal is another option, keep it below max for the main parts and kick it up to full for solos/single note lines. I just use mine for swelled notes.