On several occasions I have been asked which pony I think is the best pony in Equestria. I hate this question since most of the ponies, especially the Mane Six, have some facet of their personality that makes them endearing.
However my two most favorite ponies day in and out are Twilight Sparkle and Applejack.
Twilight since I appreciate her intelligence and her willingness to discuss a wide range of topics with me and any other pony. Although Petina strays into areas and topics that Twilight lacking in knowledge or willingness to discuss readily.
Applejack because her work ethic and down to earth honesty make her someone who stand your side through thick and thin. Also her commitment to the Apple homestead is commendable.