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Depending on the type of tile, you could use either a good quality
mastic adhesive or thinset. For all practical purposes, either will do
a good job. The premixed mastic will be easier to use though.

If you use a thinset, I always recommend using a latex modified
product. Laticrete makes some good mortars and you can buy them a
Lowes.

For backer board, I like Hardi products much more than Durrock. First
of all, the Hardi board is smoother and easier to cut. It doesn't
smell like someone just puked either, as the Durrock board does.

Latex modified grouts are more durable than their less expensive
cousins.

Felt paper makes a good backing for the backer board. I have a couple
of tile setter subs who swear by Tyvek for this type of application.


Ajax- Thanks for some great info. I've got one more question:

When I set the tub in place, normally I would need furring strips on the
studs to even out the line where the backer board comes down to the tub.
I was thinking of using thin plywood back there instead of just furring
the studs. This might add rigidity. Any thoughts?

Marc