OK, I don't really just have $30 to spend, but here's the deal: I just bought a new MacBook Pro Retina 13" to replace my MacBook Air 13" (2011) which I'll be giving my daughter. I'll want to transfer my identity/stuff over from my Air to my new rMBP. It's my understanding that the fastest way to do that would be via a Thunderbolt cable. Well, a simple Apple-branded cable costs $30. For that same $30, I could buy a Thunderbolt-to-Gigabit ethernet cable. I know that the former should be faster, but after I've used it once, I'm not sure when I'd ever need to use it again. Whereas, I can imagine a couple of scenarios where having Gigabit ethernet with my MacBook could come in handy. So what else could I do with a simple Thunderbolt cable? And just how much faster will the transfer speeds with that via using Gigabit ethernet (which will only help me in one direction with one of the laptops, while the other will need to connect wirelessly over 802.11n).