This handsome, brick-and-stone former carriage house for a 1903 Rittenhouse mansion is now a boutique-y inn with the vibe of an elegant European B&B. Lovely, homey touches abound. There is a juice bar and freshly baked pastries at the free continental breakfast. You can enjoy wine and other refreshments by the fire in the drawing room every evening, and the bedtime chocolates come from Philly's own Shane's Candies. The décor throughout is a combination of mix-and-match antiques, modern comforts, and traditional styling. Superior rooms add a plasma television and a rain shower; deluxe rooms a fireplace.
The staff is unfailingly polite and competent, and they shine in the little ways that count. Rather than offer overpriced, $40-a-night valet parking (the norm for hotels in this—or, really, any—part of town), they instead will help you with your luggage, then point out on a map various nearby garages where you can park yourself for just $15–$20 a night.
One note on location before you get too frustrated trying to find it: Despite the address, Rittenhouse 1715 is actually located a block and a half down a on a quiet, leafy side street stretching east from the southeast corner of upmarket Rittenhouse Square. (It's not as if the hotel is trying to pull a fast one or anything; this street is, indeed, also called "Rittenhouse Square.")