Hi adam
Have a great holiday, we haven't been to the Turquoise but it is on our to visit list as, like you say it has very good reviews. We stayed at the Hemera in Side in 2008 and found the town really nice. If your girlfriend is anything like my wife she'll love the shops. Plenty of clothes, shoes, bags and jewellery shops spread around the narrow streets. Most traffic is banned from the shopping streets but they are not peadestrianised. Just remember to haggle and don't be tempted to buy in the first shop you see. Look around as the prices can vary a lot.
Can't remember if there is a market in Side but the local big market is in Manavgat. Again loads of genuine fakes but watch the quality and as always haggle until the price is what you want to pay. If they won't come down to your price move on. Most tour operators will combine a trip to the market with a visit to the waterfall and river cruise. Very nice way to spend a day.
You have ruins in Side, temple of Appollo, ampitheatre etc and other very impressive ruins at Perge and Aspendos. Worth seeing if you're into culture.
When down by the harbour watch out for the Turtles. There are bars / restaurants that advertise tables watching them. Nice way to spend an hour or so with a coffee, or maybe something stronger.
As the Turquoise is a quality AI you probably won't eat out much but if you do from what I can remember the restaurants overlooking the water were quite expensive. Still sometimes the ambience is worth paying for.
Have a great time. You will love Turkey and the Turkish people.
Dave