After agonizing over this for quite a while, I think I finally have a plan to cover my walk-around and general purpose/family/vacation needs the best:
Tamron 17-50 f2.8 ($425)
Canon 28-135 f3.5-5.6 IS ($380)
This package gives me excellent low-light shooting performance (especially the Tamron, although the IS on the Canon will also help), very reasonable cost, great range coverage, and both lenses have excellent professional and consumer reviews.
I had settled on the 28-105 f3.5-4 for just $229, but decided to upgrade to get the IS and longer reach for only $100...28-135 IS has slightly better reviews too.
One lingering question in my mind is to go with a Canon 17-40L instead of the Tamron...benefits would be build quality, usable on FF camera, and faster focusing. But I would sacrifice some reach, low light shooting, and pay an extra $20.
As always, I'd appreciate any input or suggestions...
PS. This thread is for shorter distance general purpose only -- I have a Canon 85mm f/1.8 and may get other primes (50mm f/1.8 or f/1.4) to cover indoor sports. I will get longer zoom(s) for outdoor sports.