Account and Class setup

I have a services firm and would like to track service cost and revenues (that my employees provide to customers) by job. I also want to track non-payroll expenses by departments (sales, marketing, admin, etc.). How do I set up my Chart of Accounts? Do I use Classes, if at all? Should I create a separate account for each type of payroll and non-payroll expense (by department)?

[mwieder]

I would use classes instead of different accounts. Name the classes by dept. i.e. Sales, Marketing, etc.

[Mom]

Identify departments with Service Items. Identify employee by Class.