It's still early in 2013 so hopefully there will be plenty more albums to choose from by the end of the year. Meanwhile, to keep up with new developments you can get an list that's updated daily and divided into top US and UK selling albums, as well as other categories - you can find it here.
As for the best, it depends on your taste, but the album causing the biggest sensation this year is David Bowie's new one, The Next Day. This is Bowie's 24th album, but it was the first he had released for 10 years and many fans had given up hope that he would make any more music. It came out on 8 January on his 66th birthday, and along with the news of the new album was an uploaded single, Where Are We Now? Which was available free and became a huge sensation within hours. Since then the whole album has gone on sale and looks like being one of the biggest successes of 2013.