In reply to Kolya:
It's a lovely place; I go there a lot for work.
Surfing is not as good as the other Canary Islands. On the east side of the Island, Playa Nogales is your best bet, but it seems to be either flat or vicious. Playa Nueva, between Tazacorte and Puerto Naos is also good for surfing.
Hiking is great all over the island. As well as the obvious walks along the ridges and in the caldera, don't miss the spectacular walk through the water tunnels to to the springs of Marcos y Cordero. You can get a taxi to the start of the tunnels if you want to take the sting out of it.