I've been working (working: v. to write one or two sentences with the intention of finishing it up later that day, or the next day, or...) for a while on a post about how to pick which companies to apply to. Jon Pincus, my former manager from Microsoft, has done a better job that I would have, so I'll just let him take it from here... Jon Pincus: "You probably won’t be able to get your dream job in your next job; what you want is something that’s noticeably closer than where you are now, and makes it a lot more likely that the following job has even more of the dream job characteristics."
Or, if you're one of those people who want to go to a big company and are just trying to come up with names, Google Sets can actually be useful here. If you put in Google, Microsoft and Apple, it'll return related terms such as Intel, Sun, Yahoo and Blackberry. It's not a perfect list, but it's a start!