Think the airport with Ryanair is Tenerife South which serves the resorts of Playas del Americas, Los Cristianos and costa adeje, they are all beside each other - less than an hour away if I remember from the airport via coach transfer, probably take less time in a taxi. Playas del americas is fairly young and lively and can get messy so if this is not what you are looking for then you should stay clear.
Lots of touts to watch out for too, day and night they approach you in the street with scratch cards, its a scam.
Los Cristianos is a nice area lots of bars and restaurants lovely apartments and hotels, and nice quieter beach - prices are fairly reasonable too.