Aitch.

Aitch, bitches.

Haitch because aitch just sounds wrong when it begins with the letter "H" anyway.

Haitch

English isn't my first language but I don't pronounce it like a weirdo (if I did, then that'd be worrying considering I've been learning English for 15 years), so I pronounce it Haitch.

On its own its pronounced as 'Aitch' but when its used in a word its pronounced with emphasis on the 'h' sound e.g. hotel. 'Haitch' is incorrect and it really annoys me