Physical CPUs, not Logical.
You can't have two ACTUAL processing units in the machine. Logical CPUs (cores) it supports more than one for sure.
Dell probably recommend professional because of the other features, and for a laptop I'd agree.
- Encrypting File System - Usefull to secure your sensative data if your laptop is stolen.
- Presentation Mode - For connecting to projection systems for mobile-meetings / presentations.
- Windows XP Mode - XP Virtual Machine for installing those apps that don't port up well.
Either way Home Premium should be fine for you.