"I can't thank you enough for your guidance, counsel, diligence, effort and your ability to deliver the result I wanted.  I will always be grateful.  Thanks again ... ."

"I am writting this letter to express my sincere appreciation for your assisitance with the ... contract negotiations.  Your dedication and professionalism are above reproach."

"Again, thank you for your service ... Great work!"

"As always - great advice.  Thank you for your outstanding legal services.

"It has been a pleasure to have you provide legal services to us and hope to continue this relationship as [my company] grows."

"I want to thank you for your expert support ... . Your efforts enabled us to put forth a final solution that I believe effectively neutralizes some of the concerns previously voiced by [the client].  I greatly appreciate that we were able to arrive at this solution without compromising the [company's] position on many of the particularly onerous contractual conditions proposed ... ."