As already mentioned, diet most certainly plays a significant role in overall "taste" of any meat, game or otherwise.
For my personal taste, the deer I've killed that seemed to be existing on browse and acorns, at least at the time of harvest, were my favorite. I've killed several "grain-fed" deer also, and I sincerely believe a distinction in overall flavor can be made. Now, to be honest, a deer's diet may fluctuate highly throughout the year, as well as throughout its lifetime, so its hard to know exactly the overall impact food sources alone may have on venison cumulatively.
That being said, over the past three years, on three separate occasions, I have had the opportunity to kill both a buck and a doe in a single hunt, minutes apart, from the same stand, during the peak of the rut. Both stomachs have always contained similar foodstuffs. Would I say there was a distinguishable difference in overall flavor between the doe and the rutting buck? Yes, I would. Even though I am extremely careful in how I handle the carcasses (avoiding tarsal glands, quick field-dressing and cooling of the meat, etc.)
I do believe that something may be said for the amped-up hormonal levels within a rutting buck having some impact on the overall character of the venison.
Now, pre or post-rut bucks, these have not seemed to be nearly as "distinctive" in overall venison flavor to me.
Just my opinion gleaned from years of comparative analysis. I'd like to think I'm not too heavily influenced by the "power of suggestion" in my assessment, but.... you never know. =)
I just think its a whole heckuvalotta fun to compare different animals taken in different settings and scenarios. Great thread, folks, and thanks for sharing your thoughts and experiences!