The ones I would pick from the choices above would be Chakrit/Janie and Num/Joy Rinlanee.
I have alot more on screen couples that I greatly admired including: Ken/Ann, Johnny/Jariya, Por/Pat, Dan/Sara, Tik/Aom, Tao/Nat, Num/Vicki, Willy/Angie, Pete/Kathaleeya, Pete/Katrina, Passon/Ning, Andrew/Buachompoo, Sarawut/Bee and Paul/Joy Sirilak.