Unless Finale has gotten severely bloated and horribly unoptimized, older versions used to run quite well on my old single core Athlon XP, lol. An i5 of ANY kind should be plenty.
We're not talking hardcore music production with Finale. It's just notation software. If it were "true" music production software, it would benefit a little from an i7, but it's not. I think the guy at Staples just assumed that was because he actually had NO idea, lol.
If you ever plan on doing a lot of video editing, get an i7, otherwise, get an i5. Even that will be WAY overkill, actually.
The official hardware requirements for Finale 2012:
http://makemusic.custhelp.com/app/answers/detail/a_id/3545/~/system-requirements-for-notation-products
Finale 2012 for Windows®
XP/Vista/Windows 7 (64-bit compatible)
DVD-ROM drive (for installation)
800X600 minimum monitor resolution
Minimum 512MB RAM (1GB or more recommended)
600MB hard drive space required for software and user manual. An additional 2GB hard drive space is required for all VST/AU sounds included with Finale 2012
Finale 2012 for Macintosh®
G4 or higher recommended. OS 10.5-10.7 (Mac-Intel or Power PC)
DVD-ROM drive (for installation)
800x600 minimum monitor resolution
Minimum 512MB RAM (1GB or more recommended)
700MB hard drive space required for software and user manual. An additional 2GB hard drive space is required for all VST/AU sounds included with Finale 2012
Nothing at ALL about the CPU, and certainly not an i7.