Deore is fine. Having used everything from department store garbage to XTR, I think Deore is right at the point of diminishing returns for most riders/conditions unless you're competing at a high level. Even then, sometimes when you put parts on the scale the XTR/Dura Ace will weigh the same as the next level or two down.

Can I suggest drop bars on this MTB? I can't imagine doing a century on flat bars.