If you don't mind being a bit further afield, B&B I Giramondo is perfect. It's out past the Vatican City, almost at the end of the B line on the metro. There are parks, trattorias, restaurants, laundromats, gelaterias, grocery stores...everything you'll need and a lot of things you won't. The B&B itself is well appointed, clean, and comfortable. It's in a safe and secure apartment building (you have to either have a key or be buzzed in), and the apartments themselves don't have doorknobs (just doorknob keys).
We stayed in the double room, which had two twin beds, two nightstands, an armoire, a ceiling fan, and a TV. We were also the only residents for a couple of days, so we had open access to the bathroom next to the room (it's not en suite, but it's close enough). There are actually two bathrooms in the apartment, one with a tub, one with a shower stall. Beyond the three bedrooms and two bathrooms, there is a good-size kitchen, with all the things you might need for a vacation; a small dining room; a roll-top desk with little tourism pamphlets and magazines; a large living room with a sectional, a TV, and videos; and a wrap-around balcony with views up and down Via Gregorio VII.
Mario was a most attentive host. He stopped by every day to top off the toilet paper stash and drop off breakfast for the next day (cereal, croissants, wee packets of Nutella, blood orange juice [quite possibly the best orange juice in the world], milk, etc.), and he swapped out the towels every three days. He chatted with my sister in Italian and me in Spanish, and gave us great tips for local dining and shopping. We couldn't have asked for a better host, or a better B&B. Next time we're in Rome, we'll be back.
