Looking for course book recommendations

I am a teacher in Peru teaching privately to small groups of students. I am interested to know what course books people recommend. I am using Headway at the moment, but am not sure it's the best.

The books need to be appropriate to adult learners, (Preintermediate to Advanced) with plenty of speaking, listening and pronunciation activities (that's what the student's want) but also sufficient grammar etc.



Many of the students are also interested in business English so if anyone also has information on good business English course books, that will be great.



Thanks in advance. Tom