1) Although I've played the mainline games through at least once each I haven't done a repeat playthrough of any of them since gen 4 (unless you count the remakes). As a result I have more nostalgia and bias for earlier gens for better or for worse. Also I haven't done the postgames of 5 and up (except for the Delta episode in the gen 3 remake)
2) I don't PvP. I'm basing my list off of what I think looks good and not how it performs in battle or what it can learn.
3) I haven't watched the Anime since Jhoto (really since Yu-Gi-Oh started up) Aside from a season or two of Diamond and Pearl. As for the movies I've seen up as far as 12 but that was years ago.
S - I have lots of things I like about them. They both look cool and typically are either portrayed in a cool way or I just have a fondness for them. The top five could be rearranged depending on the day of the week really.
A - Overall I still find them great. I still have lost of good things to say about them though but not everything can make S tier;p
B - Really middle of the road for me. Designs here just don't interest me or have some flaw that's keeping them distinctly average for me.
C - Is really just an extension of B but the flaws are bigger. Overall their meh for one reason or another.
D - I just don't really like the design of any of these. I don't consider them bad I just don't like em. In some cases it's their color or how they stack up with the rest of their line that lands them here.
E - Now I'm just straight up asking: Why do these even exist? Some are ugly, some are uninspired and some are both. Enough said.