The many book stores dotted along this strip can provide hours of inspiration. Aside from those selling new books, several specialise in second-hand and antiquarian books.
Old townhouse style building set in front of juxtaposing high risers makes for an odd placement, but internally it's a quirky spectacle. One half is dedicated to the sale of antiques - anything from old door handles to hallways lined with hunting trophies. The other half is a relaxed bar and hidden gourmet dining area constructed of similar furnishings [all for sale too]. Even if you don't wish to spend £'s, a walk around the place is advised.
I can't pass without dropping in, Orcs Nest is a small independent boardgame, D&D etc store that's been around forever(1987)... and has the best logo. Good selection of games for younger kids too.