Did she ever say Thank you for her Christmas Presents? You need to take your own advice, that which you gave on another thread. Flowers, if you are determined to buy her something.
No no no not lingerie its too personal and most women know what they like and what they would not wear. Nor would I buy jewellery - again personally I don't wear any so it would be a waste. How about something like a voucher for tickets for a show/meal for two so she can take a friend?