I have so, so many favorite couples. Definitely high up there would be Do Min-Joon and Cheon Song-Yi from My Love From Another Star.
This show was extremely popular and for good reason as it delivered a sweeping romance that was so cute, funny and emotional. It was impossible not to root for such lovable characters who become bickering neighbors to unlikely friends to even more unlikely lovers. I’d consider this a noona romance but since Do Min-Joon’s character is an alien who lived for hundreds of years I suppose it can’t classify as one, lol.