Do all magsafe power ports have the same form factor? I have a MacBook6,1 with a 60W magsafe power adapter.  The cord on the adapter got chewed up by my rabbit (she's fine) and I would like very much to replace it.  But I really don't want to spend the $79 on the Apple Store!  

I've seen magsafe adapters for as low as $27 elsewhere, but the connectors look different than mine.  

This link, from Amazon, also 60W, claims to work for MacBooks (all of them, or some of them?), but is much less expensive: http://amzn.to/f3Xsc7

Inspecting the connector in the picture, the only difference I can see is mine is "L" shaped and the the one in the picture plugs straight in perpendicularly.  If the connectors have the same form factor and the power specs are the same, it seems that I could get away with the cheaper one.

So, will all magsafe adapters plug into my macbook and charge it?
Yes - the computer side of things is the same, but the newer cord layout is needed for Airs or when the space around the port is restricted.

The 'L-shaped' MagSafe adapters were just a newer design which meant the cable went backwards instead of outwards.  They should fit just fine and I've used one or two third-party ones in the past.  Just as long as you pick the right power-output you should be fine.  Here's a TUAW article on the matter