In 'Uta Koi' the sky and clouds are often drawn as if they were period Japanese art. It's like watching animated ukiyoe or maki-e from the Heian period.
'Tytania' has beautiful characters and costuming - kinda like Baroque European Duchies In Space.
There's a bunch of drippingly gorgeous OVAs done by Makoto Shinkai,
like Voices From a Distant Star, and Places Promised During Our Younger Days,
BUT all of his works have plots slower than watching paint dry, so it's better to
find AMVs using his stuff - at least they're over in 3 to 7 minutes a pop and you
usually get to see all the best scenes (just like movie trailers cull 2 minutes of the
most exciting scenes of an 8-minute movie.)
If you want "What If The Whole World Looked Like Ireland," then Fractale is the perfect ticket.
Last Exile Season II (Fam of the Silver Wing) had beautiful characters, landscapes, and steam-punky machinery to boot.
If you've had enough Myazaki for a lifetime, 'Princess and the Pilot' is a nice break from Miyazaki's standard clichees: heavy-handed environmentalism, Anyone in a Uniform is a Total Jerk, the Mandatory Geezer-ess, and the Plush Toy Pet Companion.
'Sword of the Stranger' and 'Summer Wars' are also highly detailed OVAs and very pretty to watch.
