become the standard way to connect external peripherals to PCs; it's also commonly used on servers for devices such as printers.
There's a spec for wireless USB but, like other standards intended to connect peripherals to computers wirelessly, it's never taken off. The current such "personal area network" getting the most buzz is My WiFi from Intel.
USB's primary competition has been FireWire, Apple's name for IEEE 1394. Unlike USB, it does not need a host computer and is faster than the USB 2.0 generation. However, it didn't catch on widely in the computer industry outside of Apple (which is phasing it out in favor of USB) and video equipment.
TCP/IP refers to the combination of two protocols: Transmission Control Protocol and Internet Protocol. Together, they are among the most important pieces of software underpinning the Internet which transitioned to using TCP/IP in 1983. Work on TCP began under the auspices of the Defense Advanced Research Projects Agency (DARPA) a decade earlier but, along the way, the software stack was re-architected to add IP as the early Internet grew.
Like many of the Internet's building blocks, TCP/IP was firmly entrenched before commercial interests got involved to any significant degree and, indeed, before most of the world at large had any real notion of the Internet's existence. The general public came to know the Internet through the World Wide Web, an outgrowth of Tim Berners-Lee's development of HTML at CERN, in the 1990s. Thus HTML, as well, is a key standard.
At the time that TCP/IP was gaining momentum, the International Organization for Standardization (ISO) spearheaded a large project to standardize networking. The "OSI model" remains the standard way to think about layers of the networking stack. If you talk about a switch being "Layer 4," you're using OSI terminology. But the specific protocols developed to go with the model were never widely used. (TCP/IP largely maps to the layers defined in the OSI model.)
The x86 architecture is perhaps the canonical example of a de facto standard driven primarily by a single vendor: Intel. Microsoft Windows is also in the running, but it was very arguably x86's ubiquity in a segment of the market open to relatively low-cost packaged software that made the rise of Windows possible. Over the past decade, AMD has also driven x86 innovations--most notably 64-bit extensions. However, it was Intel that had the biggest hand in shifting the industry from a structure in which each company did everything from fabricating processors to writing operating systems to developing databases to one in which different companies tend to specialize in one part of the technology ecosystem.
x86 emerged as a dominant chip architecture for a variety of reasons. IBM designed Intel's 8088 into the first important business PC. It got this win and others at a time when the world was rapidly computerizing. And Intel optimized itself to ride key technology trends while divesting itself of businesses, such as memory, as they commoditized.
Finally, here are a few others that could make a list like this one:
Wi-Fi played a big role in making personal computers more mobile--which is why Intel pushed it so hard.
VGA is the computing video standard that finally helped merge a rather splintered landscape and had a good long reign. (The latest video interconnect trend is a shift to HDMI--representing a coming together of computing and consumer electronics standards.)
SCSI was the first storage interconnect to merge in a big way a disparate set of existing connection schemes, both proprietary and more or less standardized. However, storage has remained an area where different standards are used for different purposes. That's changing to a degree with SATA, however, which we now see in both PCs and data centers.