Which technologies must any good IT executive examine in 2008? The list includes green power, unified communications, virtualization, mashups and social software.

Gartner has identified the “Top 10 Strategic Technologies for 2008,” and is urging IT executives to think about the risk of not implementing each one. If your competitor masters one of these technologies and you don’t, will you be at a strategic disadvantage?

Gartner analysts David Cearley and Carl Claunch reviewed the list Tuesday at the Gartner Symposium/ITxpo in Orlando, Fla. Here’s a summary:

1. Green IT

This one is taking on a bigger role for many reasons, including an increased awareness of environmental danger; concern about power bills; regulatory requirements; government procurement rules; and a sense that corporations should embrace social responsibility.

Chip designers have realized that lowering per-core performance by 20% actually cuts power usage in half, so adding cores can improve chip performance and efficiency, Claunch said.

But IT is still responsible for 2% of all carbon releases, and it’s coming from many sources. “Fast memory is getting to be a surprisingly high energy consuming item,” Claunch said.

One of the next steps is taking the power-saving features of mobile devices such as phones and laptops and bringing them to more computing platforms.

“We’ve been confronting the power problem on mobile devices for a long time because of those pesky batteries,” he said. “We can take those learnings and put them into servers. In the future, we’ll have servers that will go to sleep if they’re not being used.”

2. Unified Communications (UC)

UC functionality is drawing from five core markets: voicemail, PBXs, e-mail and calendaring, IM, and conferencing and collaboration. The key trends are communications becoming IP-based, analog systems switching to digital, and growing integration among voice, network, storage, sensors and video technologies.

“In a world in which all the information is digital and carried on IP, the opportunity and advantages of carrying it on a unified infrastructure are becoming obvious,” the analysts stated in a slideshow presentation. “Organizational issues must be addressed to take advantage of this unification, because responsibilities and budgets are so often fragmented among groups such as building maintenance, voice communications, data communications and storage administration.”