The horizontal numbers row is meant to work together with typing. For anyone who knows how to type properly, it should be faster and more natural -- you don't have to remove a hand from the keyboard.
The only exception to this that I can see would involve using calculators or similar applications, which require input of a bunch of numbers and zero text.
I use the numbers row exclusively and would prefer a keyboard without the numeric pad if I could find a split ergonomic keyboard like that, to shorten the reach distance to the mouse. From what I've observed among my friends and coworkers, most programmers, admins and other 12-hours-a-day computer users do the same, while most casual users seem to prefer the numeric pad. No offense to anyone here was intended.
