Three standout artists come to mind for me: Chris Uminga, Karen Hallion, and Amy Memberson. I didn't purchase any of the lithos from Amy although I adore her Pocket Princesses comic and you should totally check it out (these were Disney commissioned and a little high priced for their size plus she was giving away free sketches with all but the litho I wanted to I passed)!
Karen Hallion's Fairytale Who series is amazing! I got a print of Belle (below left), picked up a few for friends, and even made her Cinderella Who business card a fridge magnet. My sister grabbed her Rapunzel and Alice notecards to frame as well. What's great about her prints was they were not exclusive or priced up so if you are Disney and Doctor Who fan you can nab them on RedBubble or Etsy no problem!
The Merida (above right) print I purchased from Chris Uminga's booth (which he kindly signed for me) was a NYCC exclusive but also introduced me to his awesome art! He has tons of awesome pop culture prints and even an adorable UP/Batman mashup! In Artist's Alley we also grabbed a couple new books, some Doctor who prints, an awesome Raphael (TMNT) print, and a Jack & Sally canvas. There were so many talented artists there I was so glad to add this to my lineup!
If you are in the New York City area I highly recommend grabbing tickets next year. NYCC does not disappoint. Besides amazing art and merchandise you can stop by video game booths and play games that haven't come out yet or are brand new across all systems as well as check out new stuff from book publishers and you will find some amazing geekery around every corner! We met some great upstarts, got to explore a Walking Dead apocalypse vehicle, and so much more- Comic Conventions are not just about comic books anymore! ;)