Avi: avvy

.DOC: DOCK

FAQ: FAK (pronounced like FUCK as that's how A is prononunced here, although I don't remember saying it out loud, just thinking it like that)

JPEG/MPEG/etc.: J-P-G, M-P-G, ... (still not used to the extra E)

.PDF: P-D-F

Of course, my pronounciation with these is not as you'd think it in English. If there is a vowel in it I usually think it as one word, like avi, mov, exe etc. Although I hate it when some people say AT-AT as atat, you don't say AT-ST atst. Probably because of the vintage commercials, Kenner got it wrong.