Searching for the right lens

Here we are, I sold my Tamron 17-50 f/2.8 few days ago.
My 7D just returned from Sigma (I had to give it to them to “fine tune” my 70-200 focus..more on this on another post).
Now I need to choose which way to go: prime or zoom?

Prime scenario:
I have a Canon EF 50mm f/1.8 (that plastic thing … right)
I have nothing from 0 to 50mm and from 50 to 70mm…
I shoot street.
I shoot postcards from the places I visit (wide angle, oh, wide angle!! where are you wide angle?)
Few choices available at the moment:
20mm (32mm equivalent)
35mm (56mm equivalent, a real useless lens on cropped sensors, I’d say)
50mm (80mm equivalent, good for portraits, maybe street)
60mm (96mm equivalent, good for macro, maybe portraits)

Zoom scenario:
EF-S 17-55 f/2.8 IS (well the king for APS-C, but what if I one day go FF??)
EF 24-70 f/2.8L (well the king for FF, but a bit too long for APS-C isn’t it?)
EF 16-35 f/2.8 L (a good wide-angle lens on FF, what about the APS-C then?)
EF 17-40 f/4 L (the advantage here is that is the cheapest L lens on the market, but it’s f/4…one full stop less of light…)
EF 24-105 f/4 L (very good range but, still, f/4…)

No matter what I think now, tomorrow I’ll change my mind again and again and again…
Dam shit, what is the right way to go?!