Štěpán & Laďka’s studio, nestled between Legion's bridge and Kinsky garden, is perfect for a couple or solo traveler. The hosts are very communicative, the accommodations are very modern, and the location is hard to beat. I found most sights to be within walking distance (else the tram stops right next to the place).
It's also a great place if you prefer a quieter location, but still want to be within reach of the city center & attractions.