We had a 'pick a codename' vote early in the development cycle - the names that came out of that competition were so terrible that we were all pretty happy when one of the leads overrode it and declared that the codename would be 'Chrome', presumably because he likes fast cars. When it came time to pick a real name for the product before shipping, we ended up sticking with 'Chrome' because:
During development, we'd all come to love the product deeply, and new names had a hard time breaking and bettering the associations we'd already formed with the codename.
As our lead did, people associated it with speed - shiny fast engines and cars.
In design terminology, 'chrome' refers to the non-webpage parts of the browser's interface - the toolbars, tabs and buttons - because our design philosophy was "Content, not chrome" - putting our focus on minimizing the amount of browser UI present, we felt it cheekily appropriate to name the browser 'Chrome'.
Also, I personally like it because of its relation to 'chroma' and 'chromatic' - I love the cacophony of colors that those words imply, and how that relates to the beautiful range of design across the web. Though from the looks I get when I explain this to my teammates, I'm pretty sure I'm the only one who views it this way.