One needs to look at the two-factor theory when assessing such a situation. The theory clearly illustrates the motivators and hygiene factors that are pivotal in influencing individuals to consider and evaluate employers, but also for employers to see what would persuade people.
Another key aspect in this century has been the focus on company values, ethics, culture and behavior. The corporate culture of a company would build a positive work environment which thrives to fulfill staff potential.
Just some items to look at from my perspective would be (I see most of these have already been mentioned) :
Recognition, Overtime/Standby/After hours, Team building, Remuneration, Flexible working hours, Contribution towards Medical and Provident fund, Career growth, Personal development and Mentoring.