Who's ready to take on the big dog?

Digital music services like Napster and Rhapsody have long decried the sad state of portable digital music players on the market, saying that the lack of compelling devices has aided Apple in its quest for dominance of the digital music space.

But in the wake of this week's Consumer Electronics Show in Las Vegas, a whole slew of competitors are lining up in the hopes of dethroning the iPod juggernaut, although most would likely settle for putting even a dent into the iPod family's 70-percent market share.

SanDisk, Samsung, and Toshiba all unveiled their hopeful iPod slayers this week, while other previously announced rivals from Creative, iRiver, and Sony hope to do the same.

Both SanDisk and Samsung unveiled devices Thursday that hope to take on the pencil-thin iPod nano. Both use flash memory to obtain a sleeker look than previous models.

SanDisk's Sansa e200 series is a 6GB flash-based player with a 1.8-inch color LCD screen and nearly identical dimensions to the nano. It retails for $299. SanDisk also offers 2GB and 4GB versions of the e200, priced at $199 and $249, respectively. The Sansa e200 series is set to arrive in stores in March.

Samsung's new YP-Z5 is also about the same size as the nano, although slightly thicker. It comes with either 2GB and 4GB capacities and a 1.8-inch color LCD. Like the iPod, it doesn't have an FM tuner, although the SanDisk Sansa e200 does. The YP-Z5 will arrive in stores in February.

Toshiba is releasing its new Gigabeat S30 and S60 in March, with storage capacities of 30GB and 60GB. Based on Microsoft's Portable Media Center, the new players have 2.4-inch high-resolution screens, nearly matching the 2.5-inch screen of the video-ready iPods announced last October. The S30 and S60 players retail for $299 and $399, respectively.

These entries join the recent debut from the Creative Zen Vision: M, announced in December with striking similarities to the iPod amid searing words from Creative boss Sim Wong Hoo.

The Vision: M has a 30GB hard drive, 2.5-inch color screen, and touch control system below the screen, all identical features with the latest iPod, except that the Vision: M opts for an oval scroll bar instead of the iPod's round one.

In making the announcement, Sim told BBC News that Creative plans to "pursue aggressively" a US patent the company garnered last August on a system used to navigate music on digital players. The US patent is for the interface within which songs are organized and navigated on a music player using a hierarchical system of three or more screens.

When Creative won the interface patent in August, it said it would apply to several competing products that use similar navigation systems, including Apple's line of iPods.

Although it didn't unveil any new portable audio devices at CES, iRiver was showing off its U10 series, which feature a large screen but smaller storage capacities than the iPod at 512MB and 1GB. The devices retail for $199 and $249, respectively.

Sony showed off its NW-A1000 and NW A3000 at CES, prompting Piper Jaffray senior research analyst Gene Munster to issue a research note saying, "We continue to be shocked at how Sony's devices miss the mark despite the resources that are being put into creating a competitive product. The devices feature a non-color OELD display that cannot display photos or video and the navigation of the device is not user-friendly."

Munster wrote that he expects the iPod to continue to dominate in 2006, despite the growing abundance of rival portable audio devices on the market.

"While we found that there are several more legitimate devices out now versus what we saw at last year's CES, we still believe Apple has the market beat in form factor, intuitive user interface, and the 'cool factor,'" he wrote.

As Microsoft chairman Bill Gates called up pop star Justin Timberlake onto the main stage at CES to help him hype the Urge digital music service the software giant is rolling out with MTV, Microsoft CEO Steve Ballmer was admitting to CNET's News.com that the company needs to do better on the portable-device front.

"We've got a lot of work to do," he said. "On the PC, our stuff is still the most popular stuff out there. It's not true in the portable-device space, and I think we have to do some stuff to simplify the experience."

The hoped-for ace in the hole for rivals of both iPod players and the iTunes music store, it seems, is the all-you-can-eat subscription model industry insiders have been touting for years as the future of the digital music space.

Napster, Rhapsody, Yahoo!, and AOL's MusicNow offer such services, as does indie-friendly eMusic, but none have been able to cut into the dominance of iTunes, which lets users download individual songs for 99 cents and does not support subscriptions.

"We've been pretty encouraged by the devices we've seen," Napster Chief Technology Officer Bill Pence told News.com. "We think they're headed in the right direction."