I'm super smitten with Marc Jacobs. I love that his designs are boyish but sexy and feminine at the same time. His palette always wins me over, too. I'm not a huge fan of wearing bright colors (though I love seeing them on other people) so the fact that he does muted tones is oh so appealing. I only have a few of his pieces--maybe three or four--because, these days, he's not really in my budget. But I highly recommend scouring the sale racks at Bloomingdale's for his stuff--it's the best treasure hunt you will ever go on (you're sure to discover some to-die-for mark downs).
Some pieces from Jacobs's spring line, available at Bloomingdale's.