As a drummer I would suggest something that doesn't drown out the rest of the band :o)

As an ex-wannabie guitarist, I would suggest starting with the following four ...

Distortion ( a must really, and definitely the first pedal for most guitarists )
Chorus ( gives a nice dual guitar sound, during choruses funnily enough )
Delay ( great for trying to reproduce Floyds "Run like hell" )
Wah-wah ( basically besacue if it's good enough for Hendix it's good enough for you young man!! )

You can get a plentiful supply of multi pedal boxes that give you more options, but to get the quality you can get with good single pedals you would end up spending a small fortune. And to be honest quality counts more when your stomping on the thing like a demented idiot!

If you're just starting out, and if you're skint like me, buy them one at a time and get used to playing with it well before adding in a new one.

Hope this helped.

Slim