I'm used to taking naproxen and acetaminophen together but today, in my haste, i took 400 mg ibuprofen and 500 mg naproxen. should i worry?

Probably not: One dose above the recommended amount for nsaids is not likely to cause lasting damage if you are otherwise healthy.

No, but no need to: take two of any of these medications. Try one that provides you optimal relief. One episode of the two meds you took is not any reason to worry about.

Don't worry: Taking a naproxen and ibuprofen concomitantly is not recommended but taking a couple doses together will not harm you. You are correct in thinking that the acetaminophen can be taken with either naproxen or ibuprofen.