we lived in lanzarote and owned a bar up to 2006, its like a ghost town, no-one hardly goes there due to the prices (you can get a last minute deal cheap enough), Puerto del Carmen used to be the best place but its gone really downhill fast because most travel companies are going to Playa Blanca or Costa Teguise as they have recently built them up and made it a nice new "concrete jungle"
if you still want to go to the Canaries i would stay well away from Tenerife (north and south) and go to Corellejo (spelt wrong) in Fuertaventura (also spelt wrong) as its cleaner, friendlier, quiet but not like a ghost town and none of the usual "union jack shorts and vomit laden football shirted chav brigade" that you get on the other islands.
just off topic if i was looking to go anywhere i would go back to Cuba (7/14 nights all inclusive for the same price as he canaries, ive just booked for May:d)
hope this helps, but wherever you go have a nice time:d