I think it resides in the realm of individual choice. In marriage name-changes, I think a lot of cases are where one partner simply wants to join the other's family. Traditionally, it's the woman -- and men who change their names can catch a lot of criticism for it, and run into quite a few obstacles, even legal challenges -- but it's a way of signifying being together. And in non-marriage cases, maybe they just like the other name more
But, well, back to the original topic .. I like names that have lots of vowels, and approximant sounds (l, n, r, w), and one or two 'harder' consonants. Often I lean towards semi-androgynous ones, or original names that you don't hear often, but not totally crazy (like 'Nitzan' or 'Shmuelie'). Once I listed my favorite names and figured out those similarities ... unfortunately, I've lost the list.
Still, I like names like Laela/Lila/Aile/Aila/Lyle/Kyle/Kyla/Kayla. Exception to the pattern: no Caley or Kaylee, either girls or boys. And no Aylas, because I read the Jean M. Auel books and wouldn't like to name a child after that character. And Lily is kinda nice, in a sort of I-guess-so-but-wouldn't-name-my-kid-that. Oh, and Larkin, which is a little silly, but sounds nice and kind of playful, in a good way. Knew a boy named that when I was a little kid. He was kind of funny.
And I do like the pattern in Irish names of the 'sh'-sound 'S': Sean/Shayne/Seamus is good, and I like Seaneen or Siobhan, but not Shawna or Shevan. I also adore the vowel-heavy ones: Liam is nice, Ryan too.
As for names I would not give anyone: I've sworn to never voluntarily add to the abundance of 'J' names in my family/friends circle. We've got James (x3, all on my father's side), Jim (x1, a cousin on my dad's side), John (x3 or 4, of varying closeness), Julia & Jaysa (sisters), Jane (x2, aunts), Jock (uncle), Jason (x2 sister's friend and ex), Jill (x2, friends), Jamie Jack.... there's more, but you get the point. Of course, there's also the Joe you guys know, even if he isn't quite family. Actually, I guess that is voluntarily adding to the abundance of J names in the family. But it's not my fault!
And as a general rule, I don't like names that either have very silly nick-names (William -> Willy, Robert -> Robbie, Richard -> Dick ... actually, I once knew a Richard who really was a dick...).
Oh, and no names that are far too obviously from fantasy novels: NO 'Galadriel's.
Mind you, I don't think of this as a list of names I'd necessarily like to give my kids, just names I quite like.