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

Depends whose sounds you like and exactly what type of vibe you want to put across.
Nothing wrong with hot cakes, they are a kick arse pedal. Probably the best value for money overdrive you'd find on the market.
Distortion- wise I'd suggest you also try out the boss DS1 distortion, MT2 metal zone and OS2 overdrive/distortion from the current crop. Their OD20 is pretty cool too, I've just picked one up and find the OD2 turbo overdrive setting on it rocks (much better than the original in terms of headroom - you had to turn the level all the way to match a clean tone). the old HM2 heavy metal is a good pedal too if you can get hold of one and far more versatile than the name suggests.
Thogh I currently don't use one a wah pedal should be a must have. Chorus is useful though I find I use one mostly for clean sounds now and almost never on an overdriven tone.
Delay is a kickarse effect.
If your distortion creates unwanted noise or have to switch guitars and need a mute option a noise suppressor is a good pedal to own....
Other than that I wouldn't say too many other things are absolute must haves but it is cool to have a bunch of different effects, phasers, flangers, tremolo, maybe a pitch shifter or octaver

That said I've got around 50 pedals, all manner of things.

I agree with (And subscribe to) the idea of just having a footswitch for a great amp. Don't bother with distortion pedals at all, save your money and get a tube amp. The sounds you hear on the radio and your favourite albums are going to be Marshalls, mesas, Voxes and Fenders. You can find out easily enough what your favourite artists are using by looking at a few photos and reading articles in guitar mags or online, and from there it's a case of trying out a whole bunch to get some perspective on what you like and what you hate. As you get better and your ear improves, so too will your taste. No one has asked you what bands you are into, and that's what we would need to know in order to best recommend gear to you.

So what are your three favourite bands?