I'm planning to spend five days in Cinque Terre, to hike in the area and explore the five towns. Is there one town in particular that would be a good base and where I should look for accommodation?
You should stay in Levanto, which is just before Monterosso : it's much cheaper, and you will have a lot more options regarding accomodation (B&Bs, hotels, etc).
There is a train station allowing you to go directly to all of the villages if you want to go by train.
You can also take the boat, and hop from town to town : it's really a nice way to discover the villages, I definitely recommend it.
There is also a trail linking Levanto to Monterosso if you want to hike (and then between all villages).
You should also definitely go to Portovenere (at the south side), real nice as well.