Wife & I have been to Dolomites for summer trips about 7 or 8 times now (hiking, climbing & mtb biking) – safe to say we like it over there;) I’d say, Selva would be your best bet, followed by Canazei. Selva is a bit more touristy, but there’s plenty to do when not biking, and your only just up the road from Ortesei, which is quite a nice town with a decent swimming pool. Can definately recommend the Sella Ronda (especially the Gravity/Enduro mountain bike variant).
p.s. If you’ve got a reasonable head for heights, Via Ferrata is worth a go – as is the hike down from the saddle of the Sasso Lungo mountain (up in ‘the coffin lift’:))