Cheapo option from/to Santiago Airport is the Centropuerto bus ($3 ew) - stops at Pajaritos metro on way in and city centre stop is at Los Heroes on the Alameda.
I write from limited experience of a few stopover days in Santiago between flights but I feel relatively safe in Santiago (with appropriate common sense) and find the metro a good, clean, safe enough way to get around (again, with appropriate common sense but no more than required on the London Underground).
There are some nice asado restaurants on the Avenida Cumming and the Barrio Brasil provides edgier but trendy entertainment for those as young as I wish I still was!
Some nice parks and museums and for alternative shopping experiences, there are both an old fashioned shopping arcade and a modern shopping centre on either side of the Estacion Central.
Last edited by rmb.flk; Apr 23, 2012 at 11:07 am
Reason: Adding PS and correcting grammar!