I want to buy her a bag as a present...but which ?

LOL!!! Everyone is so creative!! Gosh, I would be wooed by any one of your ideas!! JA, you are super sweet! You must realize you are VERY lucky to find such romantic and capable H-brainstormers here!

And yes, DQ and Shopmom should totally start a DH or SO training course!!
 
I agree that for the giver it is nice to give an actual present rather than just a certificate, but , as the recipient in the case of an H bag, I would definitely prefer to choose my own bag and not feel bad about returning the one chosen. That said, my suggestion would be to buy a scarf in her favorite color, or another smaller item from H, wrapped up with a gift certificate for a bag of her choice, and a card promising a nice lunch outing to select the bag. What a great boyfriend!