Steve Jobs is having a good day.

According to The NPD Group, the leader in market research for the wireless industry, Apple’s iPhone 3G surpassed the Motorola RAZR as the leading handset purchased by adult consumers in the U.S. in the third quarter (Q3) of 2008. RAZR had been ranked by NPD as the top-selling consumer handset for the past 12 quarters.

“The displacement of the RAZR by the iPhone 3G represents a watershed shift in handset design from fashion to fashionable functionality,” said Ross Rubin, director of industry analysis for NPD. “Four of the five best-selling handsets in the third quarter were optimized for messaging and other advanced Internet features.”

Even with stronger consumer sales of iPhone, and the mobile phone market’s normal seasonal uplift after Q2, domestic handset purchases by adult consumers declined 15 percent year over year. [Engadget]

Top-selling handsets and mobile phone brands

The top handset models in rank order, based on unit sales in Q3, were as follows:

1. Apple iPhone 3G
2. Motorola RAZR V3 (all models)
3. RIM Blackberry Curve (all models)
4. LG Rumor
5. LG enV2