I would go with the Jo Malone Orange Blossom, since you know she likes it, and you can buy complementary JM scents to layer with it for future gifts. They don't have to be worn together, some people like to wear one during the day and another at night, or just switch off for more variety. That could make a great start to her collection, I'm sure she'd love that. Jo Malone had an area on the website with ideas for layering the individual scents, which they were created to do nicely. It was down the other day, I'll check to see if it's back up, so you can look.... brb.
Yes, it's working. Go to jomalone.com, click on "The Art of Fragrance Combining," then click on "fragrance combining menu" and then the individual scent for more ideas.