>I'm just a 'murrican*, so I tend to use "aitch" pronunciation of the letter "H". In various videos I've noticed that some folks in the UK and Australia use the "haitch" pronunciation.
>HDMI -- I say "aitch dee em eye" while I've heard some saying "hatich dee em eye"
>Which do you use?

Ha. But you don't pronounce the letter, you pronounce the name of it. The letter itself is mostly not pronounced, except in third-person singular gendered pronouns, and generally words beginning with h+vowel. In most of the rest of the cases it's used not to denote any sound, but rather as an instruction on how to read some other letter - as in th, ph, ch, sh, gh... which is mostly useless, see at http://ndragan.com/langsr/gnorools_G.html under gh.

The case of kh is special. It generally doesn't exist in english native words, but the Russians and Arabs use it to turn the tables - the k is now an instruction that the h should be read as h (so it should have been Hhrushchov, and, btw, Bahh). And of course, it fails, the folks generally read it as kay :). And it doesn't matter whether it's UK or Americah.