I've just caught up with the annual "Hype Cycle" report by Gartner, published in July, in which the analysts discuss emerging technologies with an eye on their impact on businesses and society over different time-horizons.
Techs rated "transformational" or with a likely high impact over the short term include social networks analysis, VoIP, Ajax, mobile-phone payments, e-paper and location-aware technology, and generally Web2.0 (which I understand is intended more as an "umbrella" philosophy than a specific technology). RFID is considered transformational but still a few years off. Interesting is that the Gartner analysts shrug off corporate blogging, mashups, smartphones, entreprise IM and RSS, speech recognition for mobile devices, wikis, and folksonomies ("folk" and "taxonomy": the product of collaborative tagging), as having a moderate or low potential. Here is the matrix that summarizes their assessment (click on the image to enlarge):