For B&Bs, a good, definitive site is the AA (like the AAA, but with one fewer A). Reviews of B&Bs do feature on Tripadvisor. There's also the Sawday's guide, which throws up some interesting places, but do be aware it's pay-to-list.

Accor is a decent chain (well, group of chains, really).

Another possibility is something like a short-term apartment let. In a number of places, you can get them for as little as one night at a time, depending on demand. Sites like http://www.booking.com/ tend to feature a number of these.

Of course, if you have any particular places in mind, where you're looking for specific recommendations, do ask here!