Thanks everyone for your input! So yes, I get you don't know what focal lengths I like to shoot with - but broadly speaking I was after something good in the 3 categories I mentioned at the start. It sounds like going for Zuiko is a safe bet in most cases.
My suggestion is: the advantage of the OM system is the compactness and lightness. Therefore i'd suggest you to pick the smallest and lightest lenses you can get. As for the focal lenghts, that depends on your preference:
21mm if you really like a deep wideangle effect
24mm if you can't afford the 21mm
28mm if you want a normal, noticeable wideangle effect
35mm for a wideangle effect that is not noticeable by common people, so it works as a "normal" lens but with wider angle of view
50mm for general purpose (i'd say this is the most important lens)
85mm for general portrait purpose use
100/105mm for a more affordable alternative to 85mm lenses
135mm for a more compact alternative to 200mm lenses
200mm for model, full-body shots.
By the way, try getting a kit that 'skips' each lens on the focal list.
So, if you get a 21, it would be 21-28-50-100. Or 28-50-100
or if you get a 35, for example 35-85-135.
That way, the angle of view change is more pronounced.
I think both "28-50-100" and "35-85-135" are excellent combinations.