Why should I care about PCI-Express?

There are two key causes to care about PCI-Express:
1)PCI is an old standard dating back to the early 90's and no longer fits our needs in terms of speed and performance.
2)AGP also is in a similar position as PCI, and chipset manufacturers are killing AGP motherboard support in favor of the much faster PCI Express interface. This means you are looking at a forced shift in the graphic sector, thus you really don't have a lot of choices in the coming years. At this point (August, 2008) choices in AGP cards represent less than 5% of available cards, and the latest chipsets can not be found in the form factor.Whereas we've spent plenty of time and energy improving the speed of processors, memory, and other parts of the PC we've done virtually nothing with the main connection between many devices-PCI. As such we are stuck with a technology in our PCs and Servers that still runs at the speeds and bandwidth we were comfortable with in the 90's. PCI as we know it is holding us back - it is a bottle neck - a limitation to the maximum performance of our systems.We all want the most from our PC. To get the most out of our PC we must get rid of all bottlenecks (obstacles to performance). Finally, we must turn to the next best alternative: PCI Express.
Overall, PCI Express is an exciting advance in the area of computers. Although AGP is now starting to die rapidly, standard PCI is taking/will take longer to die off. Expect to see at least 1 or 2 standard PCI slots alongside PCI-E in all motherboards for at least the next 2 years. By that time there will be PCI-E replacements for all common devices such as modems, network cards, raid cards, I/O and more.