I generally use a 90 deg drill mill when programing as it is easy for operators to setup. I like drill mills of differing sizes since you can use say a .25in to break edges even in tight corners and chamfer holes eliminating a lot of deburring. It doubles as a spot drill for chamfering holes as well as a mill for linear moves so it is more versatile than a chamfer mill. You could also invest in an inserted chamfer mill with an insert specifically for aluminum. See the links for a couple of examples.
Drill Mill
http://www1.mscdirect.com/CGI/NNSRIT...MT4NO=67993051
Inserted chamfer mill
http://www1.mscdirect.com/CGI/NNSRIT...64395&PMT4NO=0