Strings - My all time favourites

My all time favourite and I can hear them in any mood. I am their die hard fan since my school days only. The guitar work and song lyrics they have , I  never heard in any other Indo Pak artist. Right from their beginning with 'Sar kiye ye pahad' to 'Main to dekhunga'(although it praises Pakistan) I love them all. The duo have their own unique voice and I wonder how they choose who is going to be main lead of any song of theirs.
Both Faisal and Bilal have touching as well as  soothing voice. As far as lyrics are concerned they are very meaningful and as far as I know it is written by either one's father. He must be Gulzaar of Pakistan. Even in bollywood their numbers have been on top of the charts. And seeking their quality only, Spiderman-II's team decided to put their song as Spiderman theme in Asian region. And really it was awesome.
They have worked with many Indian artists like Palash sen, Shaan , Sagarika, Hariharan , Sanjay Datt, John Abraham etc.
Some of my favourite songs from them are

Sar kiye ye pahad
Duur
Dhaani
Titliyan
Na jane kyun
Kahani mohabbat ki
Anjane
Koi ane wala hai
Mera bichhda yar 
Akhri Alvida
Meri kahani

I will surely recommend you to hear them if in case you haven't given them time being addicted to west or masala bollywood.