This one is incredibly difficult for me. You see originally I loved Bobby & Pam the most and they were my favorite tv couple until I was like 19. But then when I rewatched the show when I was 24 I came to love JR/SE more. They remained my favorites since then but thinking about it now...
This may surprise you and if you'd asked me two months ago or maybe even six months from now chances are that my top two couples would have switched places again. But here we go:
1. Bobby & Pam
(because they were more of an idealised couple who didn't cheat on each other. They might be bad at communicating at times and had their issues but they never intentionally meant to hurt each other. They were star-crossed lovers in a sense with lots of obstacles standing in the way of their happiness and yet you can't help but rooting for them to end up together.)
2. JR & Sue Ellen
(really they are more fun to watch and have incredible passion and when things were good things were very good between them. But when things were bad it was complete misery. They were perfectly dysfunctional, you want them to be together and yet you know they are not really good for each other!)
3. Donna & Ray
(in a way they were totally mismatched and at the same time they loved each other so much. It was opposites attract and they were good for each other most of the time.)
4. Miss Ellie & Jock
(the only marriage that really lasted until death did them part. They were the foundation of the Ewing family.)
5. Bobby & Jenna
(a first love kind of thing. They were fun together and acted a bit like carefree teenagers. Yet at the same time sad in the sense that Bobby was the love of Jenna's life but she was not the love of his life. So they were doomed from the get go.)
6. Bobby & April
(really romantic couple, I loved the build up of their romance that came to it's crescendo on the Europe trip. Just too bad it all ended in tears in Paris. Since otherwise they would have made a great older couple with teenage kids on the Dallas TNT version. After seeing them falling in love it would have been great to actually see them together and moving past the dating stage.)
7.Lucy & Mickey
(a romance that never got the chance to blossom fully. The way Mickey exited the show was dramatic and tragic and very well played out. But it should have happened a season later!)
8. Lucy & Mitch
(young and fun couple who keeps trying to make it work over and over again, despite some fundamental differences)
9. Miss Ellie & Clayton
(They prove that it's possible to find love later in life. Clayton fit in well with the Ewing family)
10. James & Michelle
(the first time around I loved this couple! They were young and cute and I found James so handsome. In retrospect they weren't that great but still makes my list for nostalgia.)
Below my list and honorable mentionings:
Cliff & Afton
(Afton was the best woman for Cliff. She stood by him through all his shit and supported him and loved him unconditionally. Unfortuantely he didn't realize what he had in her until he lost her)
John Ross & Pamela Rebecca
(they were the best of the Dallas TNT couples. On paper they could have been the new Bobby & Pam in the sense they were stuck in between their father's feud. They are a pairing that already had a strong support even before Dallas TNT came on the air. They were good together and had fun chemistry. So why are they not on my list?
Because the Dallas TNT writer's ruined them as a couple in season three!

The potential for the next generation power couple was there but it was never fully realized.)