Blogging Pro Theme is a three column theme with a blue top navigation bar and big search box. Comes in two flavours, with plugin support and without.
SciEarth is a 2 column Sci-Fi based theme.
YUI-Mainstream is a clean, two column theme built on the Yahoo! User Interface (YUI). Supports fluid width, 950px, 750px and custom widths with possible sidebar sizes of 160px, 180px, 240px or 300px. Widget ready.
IceCream is a fun two column WordPress theme with a widget enabled right-hand sidebar with an ice lolly image.
Pomodoro is a bright new 3 columns, “widget-ready” theme for WordPress by Headsetoptions and MandarinMusing based on design by Free CSS Templates.
Quicklime is a three columned (main content + two sidebars) theme with a lime green feel to it.
Cozupix is fresh colored widgetized theme with 2 columns in the colors green, blue and orange.