From a recording standpoint. Noel doesn't really touch Liam because Liam's voice is just incredible. Ironically Liam's voice plateaued at the same time Noel wrote best songs. In short Liam's voice and Noel's best songs come from relatively the same era.

The songs which Noel gives the best performances on from 2002-present are Listen Up, Wonderwall, and Slide Away.

Listen Up - Yes one of Liam's top vocals but Noel's version is just about equal. The version from "The Dreams We Have As Children" is outstanding. I prefer the original band version but you can tell this is one of Noel's most personal songs and he does it justice. Its one of Oasis' best songs but its a song that both Gallagher can do pretty much equally. The message is the same in each of the bothers performances but they each have their own distinct vibes.

Wonderwall - the eerie Ryan Adam's version again isn't better than the recording but from 2002 onwards this as been owned by Noel. I think Liam's kinda bored of it nowadays. It wouldn't have been the huge hit it was with Noel singing it but he can do a solid version.

Slide Away - This is probably a top 3 Liam vocal for me, if not the best. The original version is one of my favorite Oasis' songs but ironically I also think this is probably Noel's best song when he does it acoustically. He has almost always done this song justice from even the early days when he wasn't the best singer. The Chicago 98 performance is one of the best performances of the song. It is another very personal song from Noel. I think it is about a breakup with a longtime gf or something like that. The desperation is there and you here it on Liam's version too. It is kinda amazing that Liam could tap into his bothers psyche on that recorded performance. It is a song that both bothers shine on. Another reason why Slide Away is one of Oasis' best songs.

Honorable Mention: Fade Away

None. Liam's version of each song are the best.