Which engineering majors are easiest to switch into?

OP is undecided between ME and EECS and possibly others. So s/he is concerned about having to change major later if admitted to one of these majors.

However, the OP can apply as College of Engineering Undeclared (not College of Letters and Science Undeclared). This is described here:
http://engineering.berkeley.edu/academics/undergraduate-programs/undeclared