if u are more of a landscape shooter, get a wide angle 11-18 sony
if you are a portrait shooter, get 17-50 f2.8 tamron
if you like to shoot far objects, get beercan, bbc. minolta, or sony 70-200.
if you just wanna leave your lens forever on ur body, get 18-250, 18-200 sony
if you want a daily lens, 16-105 sony, or recommended KM lens, e.g 35-105
if you want sharpness, get primes, 50mm f1.4/1.7
if you want macro, get tamron 90mm, 50mm macro minolta, upcoming 30mm f2.8 sony
if you are rich, get G lenses, or CZ lenses.
If you shoot in low light areas, get a flash, hvl 36/42/56/58 (increasing strength) or the equilivant minolta flash
If you want a cheap flash, hvl 20, or 3rd party (eg. meltz) not recommended though.
since you said you want crisp family/wedding snaps, I suggest a flash and tamron 17-50mm