I'm creating an AJAX live search on a website I'm working on. Users will select values from a few dropdowns and a list of products will be returned based on what they select. Some possible fields would be: color, model, make, etc.

What type of organization of search results do users tend to find most useful? Is it better to lump them all together (alphabatized) or is it more useful to lump them together by make? In the past I've tended to group them by "make" but I'm not concerned that this will continually force some items with a make toward the end of the alphabet always to the bottom of the list. Any tips are greatly appreciated.