i prefer the cleaner look of the half windsor with spread collars, especially for business. polo collar means four in hand. sometimes i'll do the four in hand with the thicker ties so it doesn't look too ari gold (nothing wrong with that - just not my style), but i'll play around with the tie to make it look more even.
I guess it is pretty obvious what the recomendation is going to be from a guy who's name is "Fat tie knot."
I love big tie knots. I regularly sport full windsors and double Hanovers. I think they look great and do not make you look like a footballer or the guy who fixes the copier. They add balance to that huge open collar.