I have no specific eye-color preference. But generally speaking I've only ever been attracted to dark hair and dark eyes, so I am going to say brown or black. I wouldn't wear colored contacts if I were you. They look really bad, no matter how "natural-looking" they tell you they are.
First off I go crazy like a Justin Bieber fangirl (on the inside) when I see a guy with dark hair, tan skin, and blue eyes. I. Just. Lose it. But also I've never seen a straight guy wear contacts, but I think I'd still like it as long as you try your hardest to make them look natural and not the super cheap ones that look like werewolf eyes haha
A question about this here or anywhere - I'm sure you've read the story of 'The farmer, his son & the donkey' lol :-)
Do what pleases you buddy but know one thing, let it not look beyond 'normal' i. e. blue, green etc may not go with the color we have on our skin & hair. If you do have to use contacts use a lighter shade of brown since the idea has come up to your head, satisfy your urge. But desist from using it for a longer period lest you spoil your perfectly good eyes & lose your originality :-)