My first anime's were Samurai Pizza cats, Dragon Ball Z, Sailor Moon, Pokémon, Digimon and Yu Gi Oh.
Afterwards started watching Full Metal Alchemist in 2003 Followed by One Piece and a few years later I got in 2007 Naruto and it was around this time I started watching non main stream anime that was tv and started looking up anime's on the internet.
As you can see I've been into anime for many years since the 90s and have seen tons and tons of the anime.
When it comes to deciding what my favorite anime are I normally go through a period of loving a few particular shows and once I've had my time loving and adoring them I take them off my list and start over with new favorites.
For example...HunterxHunter2011 was in my top favorite anime list but once I had chance to watch and enjoy I took it off and replaced it for a new favorite and I continue to do this all time but if a show was able to make it to my favorite list even if its off it I still consider it a classic
10/10: Classic Anime I consider to be the best that appeal to me on such a raw emotional level. These types of show tend to be ones I've seen multiple times and remain favorites forever.
9/9: These shows while not being classics are very close to being classics and may reach that level soon but for now there just shows I think are great and still consider favorites and appeal to me very deeply.
8/8: Really enjoyable shows that don't quite appeal to be on a deep level but still really loved them
7/7. These shows are good but not great. Chances are I will come back to these and maybe re-watch one or a few episodes and then be done with it.
6/6. I had a really hard time getting through this anime but it still had something about that compelled me to keep watching like maybe I liked the charcther designs or maybe it had a concept I really liked but everything else felt flat.
5/5. A show I may have started watching but did not like enough to continue not because the show was bad per say but because it felt generic or there was noting presented that made me feel like it was worth investing in but over all not terrible and theres a small chance I may come back to it and try again one day.