There are a lot of quotes that suggest this pairing so no need to explain things here.

Harry and Hermione

Jk said that we won't have a Harry/Hermione romance and as I don't like this pairing I won't comment on it.

Ron and Luna

She laughed at his jokes and talked and looked at him dreamily. Does she like him? Will he use her to make Hermione jealous?

Harry and Luna

They have quite a bit in common. Both have lost their mothers, both can see the Thresals. We see a scene at the end of the book where Harry pities her as people hide her things. She even talks to Harry about the veil and we could see more of this in book 6.

Neville and Luna

I like this pairing. Neville didn't want to go and sit with her on the train, maybe because he likes her? Luna is eccentic and we haven't seen many girls interested in poor Neville and I think that Luna would like him.

Harry and Cho

Sure they went on a date but I have the feeling that Cho only went for Harry not because she liked him (though she may have) but to find out all she could about Cedric's death. She didn't get any details and Harry found this annoying about her. He doesn't seem to fancy her anymore but time will tell.

Ginny and Neville

They went to the Yule Ball together though Ginny only said yes as otherwise she wouldn't be able to go. Also, Ginny may be the other only girl that is nice to Neville apart from Hermione.

Hermione and Krum

Krum cares for Hermione and Hermione was probably very flattered that he asked her to the ball as this is her first sign of a boy liking her. Though maybe she wanted to press Ron's buttons? I don't see Krum and Hermione together as they live in different countries and he is four years older.

Hermione still writes to Krum and sometimes quotes him so I see a nice friendship for them.

Hermione and Draco

Draco could be the little boy who pulls the girls pig-tails because he likes her. Draco made no comments to Hermione at the Yule Ball, maybe because she was with Krum and Draco may admire him but still, no comments made.

Also we see the love/hate thing here. Lily hated James and they married each other, will they be the next Potters?

Ginny and Draco

Can someone say Romeo and Juliet? Two hated families - one romance. Not likely but interesting.

Draco and Pansy

They went to the Yule Ball and Pansy is from an old wizarding family so it may not be the liking her but the "Draco you must marry her as she is Pureblood" thing.

Bill Weasley and Fleur