Ohoho... my kind of thread!
Anime:
Strawberry Panic!
Mnemosyne
Candy Boy
Blue Drop
Simoun
Sasameki Koto
Aoi Hana
Steel Angel Kurumi 2
Stainless Night
Shoujo Sect
I didn't like Kannazuki no Miko*, or Yami to Boushi to Hon no Tabibito**. Also, Kashimashi isn't technically yuri, it's gender swap. There's also Kämpfer which is similar in that it is a gender swap as well.
* = Kannazuki no Miko... See my review
here for my full explanation.
** = Yami to Boushi to Hon no Tabibito was way too damn confusing. It was all in really random order and well, it may have been yuri but there wasn't a very good story. It sucked hard.
Manga:
Well, to be honest I haven't really gotten into manga. But due to the way Sasameki Koto ended, I have that on my list of things to read. I haven't started any of them, but...
Aoi Hana
Sasameki Koto
Flower Flower
Girl Friends
Gokujou Drops
Hanjuku Joshi
Visual Novels:
Yin-Yang X-Change Alternative
Sono Hanabira ni Kichiduke wo (1 & 2... rest aren't translated yet)
Lightning Warrior Raidy I did not like. It has a lot of yuri, but it's like a 1980's dungeon crawler and I couldn't stand it.
Quote from Nexon;371382:
What would you recommend for a first time, Auggie~?
First yuri anime? Do
Strawberry Panic! It's #2 on my top 5. You can follow up with
Candy Boy, and then
Mnemosyne which is #3 in my top 5 (though be warned that it's a pretty hard show... lots of violence, and the yuri is only an element in the show but not what it's about... it's not a romance. There is a lot of yuri in it though. Very good anime though.).
You can do
Sasameki Koto and
Aoi Hana after that. Then well, just do whatever else you want.