Still don't get what thunderbolt is?
Once it is completely adopted, it'll take all those ports on your computer (esata, firewire, ethernet, usb, etc) and combine them into one port. You'll be able to plug in displays, hard drives, any usb device, anything that plugs into a computer into the same port. Of course though, you'll have a "usb to thunderbolt" or an "hdmi to thunderbolt" adapter for the near future. As it's being adopted, things will start being compatible with it right out of the box. Also, thunderbolt can't be added to any existing computer. It's a chip that will be soldered to the motherboard, so if you want it, you have no choice but to buy a new computer.
i just did the swap from PC to mac because i was killing a PC every year.
it has never once crashed and taken all my work with it. no blue screen, very reliable so far and its still as fast as the day i got it even though i have more than half filled the 1tb disk.
PC's only do this when they are filled with cheap, generic hardware crammed into a case that is too small for proper air flow. I built my own computer with all name brand stuff about 1 1/2 years ago, and I have not had one crash, or blue screen, or anything. It also runs just like the day I got it. I just hate the bad name pc's have gotten because of companies like dell and hp putting the cheapest components they can find into their computers.
Apple is very strict on what they allow in their computers and do extensive testing before releasing anything. This is why if you want a mac, you have to buy it from them. This is also why they are so reliable and cost a little more.
Also, I'd like to add that thunderbolt isn't an Apple technology, it is from Intel. Apple is just getting it first, their deal with Intel ends in 2012, then it might end up on PC's also. That is, if it isn't a fail.