Read the blogs!
didnt you already ask this inn your chit chat topic?Anyway its a personal choice really for 2.0.17 I like idesignsmf designs I use a modified version of Limestone myself.
um...best is obviously subjective to one's tastedid you take a look through the theme's to find one that you like?a simple search for responsive yields a fewhttps://custom.simplemachines.org/themes/index.php?action=search;basic_search=responsivepersonally I like NightBreeze