Michelle,

If you are not stuck on zooms these are gems in the Canon line that are not too expensive:

Canon EF 50mm f/1.8 II - about $75 US
Canon EF 85mm f/1.8 USM - about $300 US

They may make a nicer portrait lens than any of the kit lenses you mentioned.

As for a zoom I have this SIGMA:
Sigma 24-70mm f2.8 EX Aspherical DG DF - about $450 US

Right after I bought it I sent it back to the Sigma factory for calibration. It came back to me acceptably sharp. Good contrast and a great alternative to the pricey Canon EF 24-70mm f/2.8L USM costing 3 times as much.

If you are shooting portraits you will want to have the ability to shoot in lower light situations so a lens with an f2.8 is great and also for controlling depth of field with a larger f-stop for selective focus.

Have Fun!
Jeff

zingpix.com