Who's the better one at making melodies?

That's an impressive list. I'm especially impressed at the inclusion of Mr. McCartney. Most people dismiss him because of Lennon, but the Beatles songs McCartney wrote are some of the best.

Brian Wilson too. He had a sound going on in his head that has to single him out as a genius.

I love Beethoven but I don't think he's any different to McCartney or Wilson (or Bowie, to throw another one in there). We can't elevate him just because he's of a different era. Although the Eroica and Moonlight sound as good as anything that's ever been written.

Buddy Holly I don't really know enough about to comment.

This is such a difficult question, but my top melody makers would be:
Kurt Cobain, Pachelbel, McCarthney, the Vaseline's (as a duo) and Lee Marvers. I could say Kim Deal and Frank Black from the Pixies!
"Gi - GEE - ant- DIK!"

Kurt Cobain DUH!!!!!!! Wolfgang Amadeus Mozart!!!!

But of those, Beethoven

shame on who doesnt pick Bethoven. xD

Who the heck is Buddy Holly?!

Chuck Berry & Jagger - Richards all the way - Satisfaction if you have any doubts...

whoa whoa whoa, mccartney w/ no lennon? it's a commonly known fact that Mccartney focused more on rythym and timing and Lennon focused more on melody lol i picked mccartney anyway cuz he did write some of their best songs

the only 1 i know is bethoven

Beethoven has been and will remembered for centuries,anyone else...we'll have to wait and find out. The Beatles do have their legacy, but as a whole, not as individuals.