For EF my choice would be the 17-40mm so you can compliment your dads 5D and still have a decent lens for EF-s, but IQ wise it won't be a upgrade from your kit lens. Second would be the 28-70mm, this lens will be a upgrade in terms of IQ but the zoom range is not ideal for 1.6 crop bodies.

For EF-s I would choose the Tamron 17-50mm f/2.8, great IQ with fast aperture. Second the 15-85mm, the 17-85mm's IQ is not very good.

Just my two cents,

John.