Most of things have already been mentioned:
- Clifton Suspension Bridge
- Clifton Village
- Walk around the Downs
- SS Great Britain
- Cabot Circus shopping centre, (has a Christmas market at the moment)
- Blue Reef is ok but expensive, right next to Millennium Square which may be worth a look.
- Cribbs Causeway shopping centre, has an outdoor icerink over Christmas
- Museum is a good shout
- @ Bristol
- Walk around Bristol Docks
The only thing I can really think of to add is Cabot's Tower which offers some of the best views you can get over the whole of Bristol.
Aside from the Cathedral and St Mary Redcliffe those are the main tourist attractions of Bristol. You could do other stuff like visit St Nicholas' Market, go on a Banksy tour or boat trip, but in my opinion the above are more worthy attractions. The Matthew might be worth a look if it's knocking around.
As already mentioned if you can get into Bath do so, it's such a beautiful place, take the ladyfriend to Bath Spa, she will love it. (The Thermae spa, not the university

)
Enjoy
