I was never more discouraged in my faith until I worked for a church and was enlightened to the fact that the preacher didn't come up with his own sermon by prayer and meditation - instead, as he told me, his sermons came from someone else (the name I don't recall) who earns their living scheduling out the calendar with topics to preach about for that particular denomination. This pastor explained to me that that is the way it is done in all denominations as set up by the national organizations (I can't put it the way he did, but something like Southern Baptists use John Doe's schedule, United Methodist use Jane Doe's schedule, and so on.) I don't know how true it was, but I did see for myself his schedule and I was NOT impressed at all.
I didn't stay at that job but for a week. I prefer the church where sermons come from God, and services are very much like the Plymouth Brethren tradition.
As to the instruments in church - there are many, MANY people who have been blessed with a supernatural ability to play instruments who play them ONLY in praise, worship and thankgiving to Jesus. Doesn't the Bible say we are to give thanks to God for every blessing?
Of course.
Regardless, the answer to the question of the use of musical instruments in worship is, for me, quite simple. Until I am convinced of a clear, Scriptural basis for either prohibition or requirement, my "okay" and anyone else's "not okay" shall remain a matter of preference.
Just like pews or chairs, carpet or vinyl, paper or plastic. :)