If you like English historical romance, you'll probably like Phillipa Gregory's books about the Tudor reign. The Other Boleyn Girl is definitely the classic but The Boleyn Inheritance (about Anne of Cleves and Katherine Howard - two of Henry VIII's later wives) and The Virgin's Lover (Elizabeth I) are my favorite.
I'm not actually that into historical romance and would never buy the books myself but apparently having a Masters degree in history means that everyone buys me historical romance novels as gifts. I really did get into Phillipa Gregory's novels, though.
I just received
The Many Lives and Secret Sorrows of Josephine B. by Sandra Gulland for Christmas and started reading it on my flight to WDW last month - I was actually surprised by how much I enjoyed it. It's not historical romance, per say, but does have its share of romance and steamy bits. It takes place during the French Revolution and is the story of Napoleon Bonaparte's wife. There is a three-book series and I did order the second book from
Amazon and am anxiously waiting for it to arrive. So much for me not reading historical romance.