Is it proper grammar to write July 17th or would it be the 17th of July?
In writing, you will generally see 17 July, 17th July, July 17 and July 17th. The day before the month is more common in BrE, and the day after the month is more common in AmE. Most style guides will tell you which one they prefer. There is a tendency to leave out 'clutter' in modern BrE style, so you will see 17 July 2014 very often.
However, when you are reading out the date, 17 July or 17th July should be read out as 'the seventeenth of July'. Similarly, July 17 or July 17th should be read out as 'July (the) seventeenth'.
Confusion arises because of the disjunction between the written and the spoken forms.
In some old fashioned or legal documents, you might still see the full form: on the seventeenth day of the month of July, in the year of our Lord two thousand and fourteen - but for all intents and purposes, you can ignore this version these days!