Even before the recession began two years ago, people were talking about the need for Americans to downsize. What this means for the world of consumer electronics is unclear.

Our television screens just keep getting bigger and better. In 2009, the average screen size was 36 inches, up from 22 inches a decade ago.

For LCD and plasma screens greater than 60 inches, the number shipped to retailers is predicted to grow from 143,000 in 2008 to 345,000 in 2010, according to the Consumer Electronics Association (CEA).

Televisions were a hot topic at the Consumer Electronics Show in Las Vegas last week. Industry giants Sony , Samsung and Panasonic unveiled 3D-enabled sets, while ESPN announced it would bring World Cup soccer to living rooms via 3-D.

The TV gets ‘net-enabled

The market for wired TVs is also heating up, with 6.8 million Ethernet or Wi-Fi enabled sets predicted to ship this year. Online calling service Skype is getting in the action, making it possible to invite far-off friends and family to join the party via video chat, provided your Panasonic or LG TV is connected to the Internet and a peripheral camera.

These monster high-fidelity televisions come courtesy of technology advances and declining prices for materials like computing chips and screens. But it’s possible that another subversive force is at work: Competition from computer screens.

“TV has to get bigger and offer the next new rich media experience, because the PC is doing better for that screen size,” says Ping Li, a partner at venture capital firm Accel who focuses on digital media platforms.

As computers increasingly become the preferred medium for accessing content—shows, movies, music, games—they are challenging the television’s dominance (that is until the two devices merge to become one super-TV).

“It wasn’t many years ago that we used to go out and buy 15- or 18-inch TVs,” explains CEA chief economist and director of research Shawn DuBravac. “You can’t find them anymore—those sizes are extinct. They’re being dominated by notebook computers.”

But wait, what about netbooks and other minicomputers?

But when it comes to computers, bigger isn’t always better. After the first netbooks rolled out in 2007, many predicted their demise. They went on to establish a new category alongside the rise of smartphones, e-readers like Amazon’s Kindle and mini videocameras like Cisco’s Flip. The most anticipated gadget of 2010? The tablet computer from Apple .

DuBravac points out that with the exception of a few portable DVD players, there has been a void on the spectrum of screen sizes between five and 15 inches. E-readers are typically six to 10 inches, while netbooks run nine to 14 inches. At a rumored 10 inches, the Apple tablet is “right in the middle of this battlefield,” he explains.

DuBravac predicts a winner will emerge. “At any given screen size, there’s a product that has done very well,” he says, ticking off 55-inch plasma TVs at one end and GPS units and smartphones at the other.

What these smaller screen devices lack in size, they quite naturally make up for in mobility. They are great on-the-go, with lots of nifty location-based services.

But Accel’s Li says it’s less about the fact that we’re moving around and more about the ability to get any piece of data anywhere. Using these miniaturized terminals, we can access content and data on the device, on the web, or from the “cloud.” “You’re no longer tethered to one screen or one location,” explains Li.

This profusion of “screen” devices in a range of sizes is thanks to the same forces that give us bigger and better TVs: lower material costs and improved technology. Nearly ubiquitous Internet access is also key. One by one, the barriers have fallen.

The one limitation we can’t get around? Our own humanity.

“The iPhone was the first device that provided enough functionality,” explains Mark Rolston, chief creative officer at product design firm frog design. “We’re getting to a moment where we start asking more practical questions: In what context are we using these things? What are the limitations of the human body?”

For starters, the keyboard isn’t going anywhere, says Rolston. No matter how optimistic we are about future technology, if heavy text input is a core capability of a device, typing remains the most efficient solution. This means that the minimum size of laptops (and their screens) is driven by how small the keyboard can be while still allowing two hands to rest side by side on it. Beyond these human factors, our individual behaviors and lifestyle further refine which electronic devices we use and how we use them.

So even as we move toward the future—4G connectivity, the ability to seamlessly access media across platforms, and screens that appear out of nowhere (augmented reality is coming)—our humanness has the ultimate say in shaping (and sizing) our devices. With one exception: The size of your TV depends on the size of your “TV room.” And also, your bank account.