Rather than just creating a whole benefits and compensation plan, it is much better to just study what why they have done correctly and learn from them.

Business Profile:
Researches and develops drugs that cure diseases.

Culture: 

• Having a clear sense of purpose in their jobs, which is to develop safer and more effective therapies through their drug discovery efforts, especially in serious or live threatening illnesses. This clarity of vision is constantly transmitted to remind all staff, right down to the janitors that they have a purpose in reaching that goal.
• Causal work environment; Everyday is “Dress Down” day. Even the CEO dresses in jeans and sneakers.
  Encourages freedom to make intelligent risk-taking.
• Employees can ask any questions “Why” and “Why not?”
• They celebrate major milestones or wins in their company, sometimes even with celebrity bands.
• Supports employee community service and donations.
• Posters of their patients are placed throughout of their workplace to remind employees of their mission.

Benefits:

• Staff are given an average of 160hrs/yr Professional Training
• Free access to full concierge service who can provide different services such as planning celebrations and finding hard to get tickets.
• Onsite child care.
• Doggie day care.
• Daycare and nursing rooms.
• Company store on campus.
• Free parking.
• Staff are given up to 20% on their work week to pursue their pet projects.
• 6 weeks of paid sabbatical for every six years of service.
• Onsite fitness centre.
• Free coffee and iced tea.
• Ho-Hos party on every Friday evening to get to socialise with co-workers or meet new friends
• Tuition Assitance Program, where 100% of costs of up to $10,000/yr is reimbursed.
• Bring your daughters and sons to work day is celebrated regularly.
• 95% of  employees are shareholders.
• Weekly polls are conducted to ensure that complaints are surfaced and things are working in the company. They are usually quickly dealt with.

Rewards:

• Employee referral programs of up to $2000 are given to employees who refer new hires.
• Additional cash bonus acknowledging key employees who contribute exceedingly above their responsibilities.

I understand that not all companies are able to afford similar benefits offered by Genentech because to have these systems in place is costly. However, they can be a huge reason for your staff to stay long term with you, especially when they know you care about them.