Originally posted by al_undy Size/weight of the 2.8 zooms is a concern. Am I really going to go my daughter's Christmas concert and pull out a monster lens for a few shots to record the moment? Seems like overkill and I have always been a bit suspect of the folks who do. Anyway, current thinking is to start with selling the FA21 to help float the purchase of the k5 and go from there.
I'm much less well informed than others here, but:
I think you should keep your 21mm, get a Tamron 28-70 (or is it 75?) f2.8, maybe sell the DA 70, and keep the 55-300 that you have. Maybe a fast 50 as well.
Versatile, light, compact, economical set right there.