This might seem really stupid and anal, but as far as computer terminology goes, the following is a major pet peeve of mine:
Working with Flash as often as I do, I tend to hear the word “aliased” when mentioning pixel fonts. This annoys me immensely. There is no such word. I understand that it might be seen to be the opposite to anti-aliased, but it’s not. If a font is not anti-aliased, then it is regarded as being displayed normally. If you want a jagged line to look smooth on a computer, you anti-alias it; if you want it to be jagged, then you do not alias it — you leave it as it is. If, on the other hand, you have a blurry line and you want to make it sharp, then you sharpen it.
Similarly, .gif is pronounced jiff, and not in anyway like gift. This one is abused so frequently that I’ve long since given up caring. [edit: I found this supporting evidence on Google.]