I admire you.  
我佩服你.

You're really cool.  
你真酷.

You're amazing.  
你真了不起.

You did a great job.  
你做得很好.

You really impress me.  
你令我印象深刻.  

You're an outstanding individual.  
你真是杰出人材.

You are a great asset to our company.  
你是本公司的重要资产(台柱).