DL the Elder and I found The Table Bay Hotel fabulous. Granted we had one of the few rooms with a terrace (and the most spectacular view of the mountain) but the room was pretty spacious. It also has a lovely pool and a fabulous spa. Sure the V+A waterfront is touristy but it's packed with lovely eateries and bars and plenty of activity. Yes, an appartment/suite will give you more space but do you really want to be getting taxis to get everywhere and worrying about security?. The Table Bay is also attached to the shopping mall (great when it's really windy outside).
I second Highflyer's recemmendation for Balthazar - great meats (cooked perfectly - nice and pink) and a sublime wine list (and less than 5 minutes back to our room [:D]). Another restaurant I can recommend is The Opal Lounge- again fantastic food and a great wine list.
Man with a van is a good idea.I used a company called Cape Convoy to do the Cape tour
http://www.capeconvoy.com/- driver owned (Rob - who was fantastic) and a max of 6 pasengers.Really informative and got to see things that we wouldn't otherwise.We walked all the way to the point - beware of the sun! My factor 20 was totally inadequate. We also used them for the winelands which avoided the need for one of us not drinking (like that was ever going to happen [:D]).
http://www.waterfordestate.co.za/ is a fairly big winery but may be less boring for Tizer.
Tizer might also like this
http://www.capetowninfo.co.za/moyo-stellenbosch. Sure it's a bit touristy but it's fun with lots of pretty edible food and entertainment (the tables in the trees are great).
I may be shot down in flames but personally I was totally underwhelmed by Robben Island. It's a guided tour in the true sense. They drive you around the island on a bus (you can't get off) and only the last half an hour is in the prison. You can't just wander about (which I would have much preferred) and you have to leave on your assigned ferry. I pre-booked this trip for the day after we arrived - it gets full quickly and will often be cancelled due to the notorious Cape winds (same as the cablecar).
The mountain is fantastic - go the first day you can (the weather changes quickly in CPT).
The red buses are another way to get about and see all the sights (Botanical Gardens, District 6, Camps Bay etc etc).
Lastly, we were there much the same time as you're looking at. The hotel had a fabulous Christmas tree but it was all pretty low key - a few decorations here and there but no piped carols in the hotel or malls (and no seige mentality shopping either). Reminiscent really of how things were here in Blighty 30+ years ago [:)].
Even if you're not there for Christmas itself you'll have a fabulous time.
DL