I like the driftwood and its placement. I like the rounded rocks. The sand looks good. I think you have a good eye, which makes the fake plants even more out of place. (I don't think you expected rave reviews on the plastic from us and so I will dish it to you).
There are plenty of nice easy plants that would give your tank a more natural feel and compliment your hardscape beautifully. Why not try it?
A wall of vals would look great. Or a few crypts. Or java ferns. And, while you tell us your plant plans, tell us about fauna too.