As technology advances, some companies carve up their own routes and niches. Like for instance Intel introduced Lightpeak which hey turned into the crazy sounding Thunderbolt. It essentially combines PCI Express and DisplayPort into a new data interface that can be carried over longer and less costly cables. Because PCI Express is widely supported by a lot of vendors and built into most of Intel's modern chipsets, Thunderbolt can be added to existing products with relative ease which makes the system backward compatible with existing DisplayPort hardware. There were even plans to link it with USB cables but the USB forum denied them access - probably they were scared of the possibility of losing their hold on the USB technology.
The Nokia N900 comes with a problem with it's micro USB port not being fixed firmly to the device. This results in it being torn of from the phone itself. You could get these cables from some optimized cable company as well. Or you could use some precaution like this for saving the micro USB of your n900.
Apple Macbook Pros come with a port known as the mini-display port. This port is smaller than conventional display ports but the drawback is that to connect it to external devices you need to buy a converter from Apple which is quite costly. Or you could also get some a DVI to HDMI cable from them as well.