I agree with the masses (and I was just thinking about this as I was rewatching some Angel). I think she looks the most adorable in Season 1 of Angel. And the most "Cordelia". Plus, she's supposed to look young. She's only 18/19 in Season 1. It did look okay in Season 2 though, still cute because it was still flattering her features I think.
And when she got so short & very blonde it just did not fit her face or body. But, I loved her hair in her Season 5 appearance. Very cuute.