Which anime should I watch next?

Out of the three you listed I would say to watch The Melancholy of Haruhi Suzumiya.

Hope I helped. ^^

Queen's Blade.

haruhi

Death Note
Code Geass
The Melancholy of Haruhi Suzumiya is cool too :D

Watch- The Melancholy of Haruhi Suzumiya

My top 15 other suggestions- (not in any order)
-Blood+
-Chrono Crusade
-D.Grey-Man
-Darker than black
-D.N. Angel
-Fullmetal Alchemist
-InuYasha
-Midori Days
-Rozen Maiden
-Soul eater
-The Tower of Druaga
-Tsubasa Chronicles
-Vampire Knight
-The Wallflower
-xxxHolic

movies-
-The girl who leapt through time
-Origin: Spirits Of The Past
-The Place Promised In Our Early Days
-5 cm per second
-Blood: The last vampire
-Lupin III: The Castle of Cagliostro
-Nausicaä of the Valley of the Wind
-Laputa: Castle in the Sky
-Grave of the Fireflies
-My Neighbor Totoro
-Kiki's Delivery Service
-Only Yesterday
-Porco Rosso
-Pom Poko
-Whisper of the Heart
-Princess Mononoke
-Spirited Away
-The Cat Returns
-Howl's Moving Castle
-Tales from Earthsea
-Voices of a Distant Star
-Brave Story

^^; all of these were my favs

Axis Powers Hetalia and Hetalia World Series (same series, they just changed the name)

Do Haruhi, it's a pretty amazing series, I just watched the movie the other day, I'd say the series is well worth it.

Code Geass is really good so is Pandora Hearts out of those three Tokyo Mew Mew

Well I really like Tokyo Mew Mew. I would recommend that one.

Code Geass.