A leaked AT&T memo uncovered by MacDailyNews says that 3GS day was the:

• Best-ever sales day in our retail stores

• Second-largest traffic day in our retail stores

• Most transactions processed via our IT systems in a single day
• 
Most upgrade eligibility checks in a single day

• Largest order day in att.com history

• Largest features sales day in att.com history

Uh, duh. What other launch day was going to be the best in AT&T’s history, the Motorola EM330 with built in FM Radio? Ooh la la. (But seriously, Apple, we kinda want an FM radio built in to the iPod and iPhone.)

The only surprising thing about this is that the 3GS, considered by many as a mere spec bump, beat out both the iPhone 3G and the original iPhone. Kudos.