Chase Sapphire Reserve is a popular general-purpose travel card. Good rewards, travel protections, and customer service. The $450 AF is mostly offset by a $300 travel credit.
Does she have a favored airline or hotel chain?
Also use the search tool. There are a lot of threads about travel cards in general.
She likes to travel United.. I don't think she has a girl preference. Being that she normally stay at resorts.. But I'll have her look at the forums here. To see what she think may fit her needs.
For a United flyer, it's hard to go wrong with CSR. Chase UR cards (Sapphire, Freedom, Ink) are an efficient way to earn points that can become United miles.
*Note that this requires at least one UR card with an annual fee. Also, I'm assuming she books her United flights through a United loyalty account (rather than a partner airline like Air Canada).