But in my opinion (and technically all these countdown posts have just been "my opinion") there were three relatively important -- but still not "major" -- characters who were better on "Angel" than they were on "Buffy" (and when I exclude "major", that means anyone who appeared in the opening credits, so no cheating by saying Angel, Wesley and Cordelia, though I'd at least debate you on Angel, and possibly even Cordy).
3. Chanterelle/Lily/Anne (played by Julia Lee)
I'll start off with an easy one. When we first saw this character, she was going by "Chanterelle" and was part of a vampire worshipping cult in the "Buffy" Season 2 episode "Lie to Me". She popped up again in Los Angeles in the Season 3 premiere, "Anne", which is where she got her new name (from Buffy). It's also apparently where she finally settled, because she popped up again in the "Angel" Season 2 episode "Blood Money", running a youth shelter. Two episodes later, she was back again, enlisting Gunn's help, and she popped up for the last time in the series finale, "Not Fade Away". For a character that only appeared three times, Anne Steele was pretty memorable.
2. Darla (played by Julie Benz)
This is another easy one, since Darla was killed off relatively quickly on "Buffy". After her dusting in Season 1, it seemed like she'd only show up again in flashbacks, but she was resurrected by Wolfram & Hart at the end of "Angel" Season 1, and became one of the major driving forces behind Season 2's division of Angel Investigations (even going so far as to have sex with Angel to try and turn him back into Angelus). She reappeared again in Season 3, this time pregnant with Angel's child, who would eventually be Connor. Still, I always thought she was at her best in the flashbacks (even if the character had to be made American because Julie Benz couldn't do an English accent), where she always looked fantastic.
1. Faith (Played by Eliza Dushku)
Now for the controversial pick. Given Faith's role as one of the major villains of Season 3 in "Buffy", plus her key role in Season 7, it'd be easy to say she was better, or at least more important, on "Buffy", but I thought the best Faith episodes were on "Angel" (not discounting Dushku's performance as Buffy-in-Faith in the "Buffy" Season 4 episode "Who Are You?"). Her torture of Wesley in "Five by Five" was Faith at her villainous worst, and she immediately followed it with the breakdown in the alley during her fight with Angel. The follow-up episode, "Sanctuary" is one of the best in the entire five season run of "Angel". But what makes Faith a better character on "Angel" than on "Buffy" is that's where her redemption comes in. She goes to jail and begins to pay for what she's done. Then, when she's needed again, in "Angel" Season 4, she breaks out -- not to escape, but to help -- and finally takes up the leadership mantle that she never could as "the other slayer" on "Buffy". And I could go on-and-on about the amazingness that is "Orpheus", but instead I'll just re-state my position: Faith was better on "Angel" than on "Buffy".