While the Motorola DROID and the Apple iPhone celebrated larger first month numbers (525,000 and 600,000, respectively), the announcement of 80,000 Nexus One devices (which translates into a steady 20,000 per week) is still a relatively strong number for Google. I'm sure Google would have liked to have broken the 100,000 mark, but the fact that they're going strong four weeks later (and their weekly totals haven't dropped) is a positive sign.
Keep in mind that the Nexus One is sold exclusively through Google and is only compatible (when it comes to 3G) with T-Mobile, so given those two things, the numbers are respectable. When the device lands on Verizon Wireless and Vodafone later in the year, I can see those numbers growing even more. The question remains - given that it's public knowledge about the Nexus One coming to Verizon, are people holding off for Big Red's launch?