Talking about old school, it would definitely be my Secondary days.
Well, after doing the videos for them, I realize that we have almost known each other for 10years...
OMG! 10 years of close friends!
Anyway, I really love those genres of English songs and I only got in touch with English songs during my Secondary days...
What made me listen to them? During my Literature lessons, we were to perform an English song and I failed it thoroughly.
This song was and is still my favorite - O Town's All or Nothing
(Although I kept saying I hate this song because it is very irritating when my best pal kept singing it to me)

What else? Of course common ones are like Westlife, Plus One, A1, BSB, Michelle Branch, Christina Aguilera, Britney Spears, Blue etc.
Especially the boyband Blue, we love to sing their songs.
Not forgetting the number one song - Lady Marmalade...