I personally round up in my head anyway...so it's $16 whichever way you put it :-P
I think there are those people out there who think that .99 is less than a dollar (well, I guess it *is*...) but I don't think it matters in the long run.
I usually for my own eccentricities price everything in 50 cent increments...I have one thing listed for .65 and it just about drives my sensibilities bonkers.