I have a hopeless defense and everything and anything will improve it. I have the choice between drafting a 95 rated LB or a 95 rated FS. Does anyone have an opinion as to what player would have more of an impact and why?
I do not intend to use zone defense and will ask the LB's to blitz.

DB - The answer is always DB. ;)

Having an elite secondary covers up a lot of flaws up front. You can get away with having mid-rated LBs as long as they are fast and have good tackle.

I've seen a couple elite rated DB's without elite rated speed.
Be careful going by overall rating. Make sure the individual ratings match what you are trying to do on defense.