Yeah, I know what you mean about sticking with one brand, as I have found a lot of particular bowling balls I have liked, but I don't know if I could build an arsenal without significant overlap.
The balls I've thrown recently that I really like:
Columbia Burst
Track 607A
Track 715C
Hammer Backlash Blue
Also, sorry to keep limiting the choices, but perhaps it make it easier to make suggestions. I won't throw AMF equipment, and unlike Brunswick, I wouldn't throw it even if it was given to me for free. That has nothing to do with the quality of their equipment, but just personal grievances with the company itself.
I would usually throw only Storm and Roto, but I don't like where Storm is at right now in terms of selection. I didn't like the Invasion, but I think the Anarchy could be really good for a strong pearl, and I don't know anything about the Prodigy. I really like the dagger, but I've never thrown anything else in the Nomad line, or anything else Roto has made besides the Cell and Mercury.
So, if you could build an arsenal from Hammer, Track, Roto, Columbia, and possibly Storm...let me know what your dream line up would be and what hole each ball would fill.
Thanks, the responses so far have been very informative.