I think the period between the release of Neon Genesis Evangelion and Gurren Lagann is my favorite. The late 90's was peak. Yeah, 80's OVAs might be the peak of actual cel animation, but the stories were often underbaked. The late 90's combine great cel animation with better storytelling and characterization. The early 2000's adoption of digipaint did lead to a bit of a dip in aesthetics IMO, but NGE was still close enough in the past that studios were willing to crank out big, weird stories in hopes of lightning striking twice. Something like Mai-Hime, flawed as it is, only happens in 2005, and I think that's pretty cool. I think of TTGL as the end of this post-EVA era. After that, CGI integration starts to really take off, backgrounds start to suffer, and in the 2010's, pretty much 90% of anime looks ugly as sin. I enjoy plenty of modern shows, and I think anime as a whole is bouncing back in the 2020's, but I will watch pretty much anything from that 1995-2007 range. It's just my jam.