Kanon 2006 is definitely worth a watch. I am yet to watch Kanon 2002 but I doubt it could be as good as the newer version, seeing as I found it to be wonderful.
Story: 9/10
The only reason I'll give it a nine out of ten is that the ending was a bit confusing - but honestly, I am very close to giving it a perfect score. The story is laid out beautifully, you get to see how Yuuichi's relationship with the female characters unfold, and it is wonderful.
Art: 10/10
Perfect. The characters' expressions, their tears, their joy - you can see it in their faces so well it almost becomes real. The detail in the scenery is extraordinary, it's nice to see the little touches.
Sound: 9/10
The music you get to hear throughout the series is lovely to listen to. It is one of my favourite things about Kanon.
Characters: 9/10
I am only giving it a 9/10 as I didn't like Makoto, apart from that, I adored all of the characters, Mai, Nayuki and Ayu in particular.
Enjoyment: 9/10
They manage to drag a fair few emotions out of you in this anime. Although I didn't cry, it did make me feel quite sad. Of course there were times when it made me extremely happy, too.
Overall: 9.5/10
I know, I'm being particular, aren't I?
I hoped this review helped.