Georgia has a classic look, but it is clearly a modern alternative to some other outdated and overused serifs. Georgia is designed for clarity on a computer monitor even at small sizes, partially effective due to a large x-height.
Bree Serif is a unique but not overly frilly slab serif that has just enough character to really give it a unique feel, without it being overly stylized.
Didot has some hairline elements in it that can disappear it smaller sizes, but it is nonetheless a high contrast, modern serif winner that is an important addition to the font lovers arsenal.
Museo Slab is a ridiculously good looking slab serif with a ton of heart and an endless amount of ways to pair it. As a title font it has character and panache.
Baskerville is another case of classic with modern uses. Don’t be afraid of going classic in a modern setting.
Rockwell is a seriously cool serif font with a bit of a hipster vibe, and a diverse array of uses limited only by your imagination.
Download Rockwell (free)
Ugly Qua is probably my favorite font on this list perhaps because of it’s tastefully unique character. It’s a display serif perhaps, and it’s uses could be in a place where you’re looking for a vintage font, but perhaps in a place where elegance is key it would play well as a refreshing juxtaposition.