One of my favorite zanpakutou release commands would have to be Urahara's: "Awaken, Benihime".
I also like Gin's: "Shoot to Kill, Shinso", Kaien's: "Rankle the Seas and the Skies, Nejibana", and Matsumoto's: "Growl, Hainiko".
For arrancar releases my favorites are: Nelliel's "Declare, Gamuza" and Harribel's "Destroy, Tiburon".
I'm probably biased to some of these on account of them being among the character's I like the most.
Suiten Sakamake...Nejibana...., Chire....senbonzakura, Soten Ni Zase...Hyorinmaru...
I guess I'll add my two cents.
Shingami: It's a tie for me between Suì-Fēng's "Jinteki Shakusetsu" and Love's "Uchikudake"
Arrancar: Yylfordt's "Tsukikudake"
Shinigami: Specifically Kaien's "Rage through the sea and the heavens" used in later episodes
Arrancar: A tie between Findor's "Carve upon the water" and Abirama's "Scrape the summit"
Cast off your fear! Look forward! Go forward! Never stand still! Retreat and you will age! Hesitate and you will die! SHOUT... ...MY NAME IS... ZANGETSU!
Most epic release of Zanpaktou. Also Shunsuii's and Ukitake's are epic too.
I like Ulquiorra's one, "Isolate Murcielago". Complete despair.
And Nnoitra's (in anime) "Pray Santa Teresa", looked epic.
I think we should write all of them,and then choose the best one. in fact,there are a lot of them which i don't remember anymore.
I like Rukia's release and zan overall.
http://www.youtube.com/watch?v=zQDvoaPQHPM (not mine )
Initial release command...the form...the techniques...they are all beautyfull...totaly my favorite in the whole bleach.
Hands down on "Hoeru ...Zabimaru!" from Renji. This is actually the one that I remember when someone mentions "zanpakuto release"... :P
I would have to say that my favorite release command would be Ukitake's sogyo no kotowari.
"All Waves, Rise now and Become my Shield.
All Lightning, Strike now and Become my Blade" I was hoping his sword was actually the strongest water type, being so powerful that it could create lighting storms. But sadly Kubo only gave him the greatest parrying weapon in all time. Sigh
This is my favorite release command. It sounds soo epic and badass at the same time and Hisagi just looked Boss with his sad expression.
I just like the way it sounds when i say it.. or when Shinji says it..
Omg. Im off to rewatch bleach
Although this might not be an actual command, but if it was, it will totally be my fav! followed by yama-jii's release command. When I first read and saw this I was jus blown away. Some other translations tho have "cutting thru time" and or "slicing thru time" that aren't imperatives but this one jus sounds more badass for me.
as for an arrancar release and altho the outcome didn't really have anything to do with the release command, I'd go for nel's release command; both Japanese, "utae" and English, "declare" sounded really cool. It looked as tho she was about to pass judgment on nnoitra. Also, this was the only release, i think, that was tried to stopped by someone which also built the hype/tension up.
I love Nejibana and Sode no Shirayuki.
But my favorite is probably Suzumebachi's. This continues to be one of my favorite scenes in the series:
Even the sound it makes it perfect.
Raise your head , wabisuke
sounds cooler in japanese though
"Flower Wind Rage and Flower God Roar, Heavenly Wind Rage and Heavenly Demon Sneer"- Katen Kyōkotsu
"All Waves, Rise now and Become my Shield, Lightning, Strike now and Become my Blade"- Sōgyo no Kotowari
These 2 releases are creative and beautifully artistic. It is unique compared to releases of other fighters and it gives you an idea that Shunsui and Ukitake aren't your normal shinigami. I wouldn't be surprised if Unohana has a long release as well
"Reduce All Creation to Ash"- Ryūjin Jakka
Badass!! Nothing more to say