Most dress codes require the badge to be clearly visible, generally meaning on the neck line. Ours specifically prohibits wearing them on sleeves (think Dean and his cig pack), or on the waist.
If I put mine on the chest pocket, it would look like Oohlala's tassels swirling! I've done the safety pin thing, but usually just the neckline. If you choose to use a lanyard, make sure it has a breakaway latch so if it gets grabbed you can't be choked. I don't like them because when you lean over the darn thing falls into your working area, if not actually whacking the pt.
I agree - stay away from lanyards in patient care areas. I have seen many instances of 'accidental' dislodgement of IV lines (including central & swanns!) as well as ET tubes, trach tubes, etc... when they get tangled with a lanyard. Also - very icky - in terms of dangling fomite around one's neck.