What to look for in a Drupal theme ? Checkout some of they key features and which themes offer those.
Theme Features Description Model Themes
Fixed / Fluid Both types are in equal Demand. Fixed width themes are more used when the website is dynamic and content is primararily added by users. This prevents distorting of website. Fluid width themes have a disadvantage, that it will show blank spaces when the screen size is bigger.
Multi-column Support Theme should support 1, 2 and 3 column layouts. If 2 column is used then theme should automatically resize the center column to occupy the 3 column space. Same applies if 1 column is used.