What is it about a workplace that makes it a "Great Place to Work," taking a perhaps previously unknown company and placing them on the cover of Fortune magazine, suddenly deluged with resumes from job-seekers?   Every company wants to be recognized as an employer of choice, even if that doesn't necessarily mean making an annual "best" list. Hal Adler, president of the Great Place to Work Institute, says the secret isn't sushi chefs and shi tzu walking services. On the contrary, the formula is pretty simple.   "Ever since 1981 [when the "Great Place" lists were started], employees have said and continue to say that a great place to work is one where you trust the people you work for, take pride in what you do and enjoy the people you work with," he says. "Benefits play a role, and though it's not the 401(k), it's not lavish benefits but unique benefits that make a workplace great."   As an example, Adler cites Analytic Graphics, where leaders purchased flat-screen monitors for employees after reaching a business goal. "It was a benefit that matched that company's culture and one employees would value. Employees at another company would want a dinner cruise, ski trip or box seats."   Adler says employers should remember that "you can't buy employee engagement. Even at Google [2007's Fortune Best Place to Work], while employees appreciate all the perks, they speak most about the relationships, feeling of empowerment and freedom to make mistakes" as what makes the company special. Relationships, he notes, are "one of the systemic differences between good places and great places" to work.   The Great Place to Work Institute is accepting nominations for its 2008 Best Small and Medium Companies to Work for in America list. To nominate your company or a peer, visit www.greatplacetowork.com.   Look for more in-depth coverage about what makes a great place to work in EBN's November issue.