Bob,
I do not think you would be disappointed in a two wheel drive tractor. I will tell you JD has done its homework on the X series, they will do things that will amaze you with two wheel drive. That said, if you are on the fence about going with four wheel drive, the option is not that great a cost, and would eliminate the issue from your mind. You might never need four wheel drive, but then again you might. One thing I have noticed owning five John Deere tractors, with a sixth on the way is that you will try things and do things with your machine you never thought you would. For example, I bought my original tractor to mow with, then wanted something to operate a small FEL, then wanted something to operate a big FEL then wanted something I could move big rocks and trees with and mow and move dirt and snow and pull heavy trailers and loads and smooth driveways and help my neighbors put in fence, etc. See, the possibilities are endless, so if that thought is creeping into your mind act on it now, don't wait, it gets more pricey later on.
John M