Long back in good olden days of Doordarshan, we used to have a program to help the farmers. This was called "Vayalum vaazhvum"..meaning, Farmfield and life.
The title music was composed and sung by none other than the great Tamil film music composer - Sri MS Viswanathan.  
This song goes like this:  
"Thaai nilam thantha varam, taavaram  
Athu thazhaikka thazhaikka varumaaru yaavarum" 
Similarly, another song from Doordarshan, which catches my fancy is about Male-Female Equality  
"AaNaa PeNNaa poranthathingay  
Athuthaan Ingu muthal kelvi…  
AaNaa porantha sirippu enna  
PoNNa porantha veruppu enna" 
Some more songs on Doordarshan songs that I hold close to my heart:  
1)      "Antha veenaikku theriyaathu  
        Athai seithavan yaarendru" - Title song of Teleserial SAHANA  
2)      The title music of Mahabharath  
3)      Mile sur mera tumhara  
4)      Junoon title song in Tamil. I particularly remember this line - "Pidivaatham theera pidivaatham vendum"  
5)      We used to have this great Mango drink called "Maaza" (We still have it, but this is a re-launched product with a new refreshing taste - which is YUCK)…this particular advertisement was telecast in Doordarshan, where Ranjit Barot - film musician and ad jingles music composer - also stars in it…it was a fabulous piece of beats for the Maaza drink