Excuse has two different pronunciations depending on use: /Ik'skju:z/ is a verb, "Please excuse me." /Ik'skju:s/ is a noun, "Why are you late? What is your excuse today?"

It's a kind of 'g' sound.. If you say 'exgyoos', that's more or less how we pronounce it.

Aspirated, unaspirated, don't make things more difficult than they are. Just listen: http://www.thefreedictionary.com/excuse And when you encounter people saying 'excuse me' (or whatever) in movies, just listen and repeat. If you're not sure, record yourself and compare.

I hear lots of "excuse" in movies, some of them are aspirated, others are not. So just let it go.