How Do You Pronounce The Names of Linux Distributions?

I think "boon" instead of "bun" is probably correct.

It seems like most words foreign to English translated into English are pronounced as they would be pronounced if they were Espanol/Spanish words.

For example, in Espanol/Spanish, "mano" (hand) is pronounced "mah-noe" (english phonetic), it's not pronounced "may-noe" nor "man-oh".
Explained further, what I mean is, most of the time, if you use the Espanol/Spanish vowel sounds instead of the English vowel sounds, it's correct for the foreign language.

Almost no other languages seem to use the "a" sound as in "plan" or "splat!". Usually the "a" sound is more like the English "o" sound as in "gone" or "shot" (ahh) or "fawn".
So for the U in Ubuntu, I usually say "u" as in the "ooh" sound in "soon", not "oo" as in "book" nor "uh" as in "under".

So I agree with PortalHavoc's preference.
You might notice how President Obama says "Pock-ee-stawn" (Pakistan) instead of "Pack-uhh-sta" or "Pack-ihh-sta".
The fuy thing is how President Bush (W) used to pronounce Iraq, several different ways with almost every vowel sound you can think of.