thanks for all the replies guys, lets switch up and say primes. What would you guys recommend for prime?
btw I'm still leaning towards the sigma 18-35mm
with this sentence from your first post in mind:
She/we need a good all-in-one lens for our travels. We'll be shooting everything from portraits, landscape, animals, etc.
there is no prime lens that will allow you to do all...
if you really want a do it all lens, from portraits to animals...you'll need one of the superzooms with more reach...like the tamron 18-270VC recommended earlier
an 18-35mm would be good for some landscapes, and general walk around...the range would work for environmental portraits...but it's a little wide for half body/head shots