The Westin Grand Cape Town Arabella Quays Hotel is that large hotel that you pass on your left as you enter the city on the N1 highway. It's the glass-covered one right next to the traffic lights that (if you were to turn right) would take you to the Waterfront.
The Westin Grand used to be known as the Arabella Sheraton, and back then (about 3 years ago now) I once had the opportunity to attend a meeting in the building. Even back then the hotel was magnificent, and from the descriptions I've read on the web it seems as though they've even managed to upgrade it somehow!
The hotel is attached to the Cape Town International Convention Centre and is right next to the little canal that leads from the hotel area to the V&A Waterfront. I haven't tried it yet, but you can catch a ride on little taxi boats that will take you to the Waterfront. Anyone else been on one?