Philly has some excellent hotel options. I recommend staying downtown in Center City so you can easily visit the historic sites and the growing list of excellent new restaurants. My suggestions include:
Kimpton Hotel Palomar: Located in a former art deco office building, north of Rittenhouse Square, this is a hip boutique property in a great central location. Their Square 1682 restaurant on the first floor, is open for breakfast, lunch, dinner and weekend brunch. It has 230 contemporary styled guest rooms. 117 S. 17th St.
Kimpton also has the Hotel Monaco which gets great reviews as one of the best hotels in town. 433 Chestnut St. It is more formal than the Palomar, but beautifully decorated.
Warwick Hotel: This is a boutique hotel located east of Rittenhouse Square at 220 S. 17th St. This historic property has been transformed into a contemporary, boutique hotel in a great location from which to explore the city. Off the lobby is Bluestone Lane, a contemporary cafe serving coffee, breakfast items and lunch. The Prime Rib Restaurant is also attached.
The Rittenhouse Hotel: This is an elegant, luxury hotel right on the south end of Rittenhouse Square. Their Mary Cassatt Tea Room is a popular spot for afternoon tea.
DoubleTree by Hilton: At 237 S. Broad St., this is a convenient property if you want to be in the heart of downtown and be able to walk to restaurants, shopping, historic sites and museums. I also like the convenient parking garage next to the hotel, where you can self-park and then leave the car until you check-out. My room was nicely appointed, quiet and comfortable. It is located across from the Academy of Music, the Merriam Theatre, The Kimmel Center and adjacent to the Wilma Theatre.
Also getting good reviews is the Rittenhouse 1715 boutique hotel, located just east of the square at 1715 Rittenhouse Square St.