hosting technical requirements

I was put in charge of developing a Drupal website to meet a business need where I work. When this was run by the team in charge of servers they came back wanting to know how much memory, CPU, and disk space a provisioned server would need to host a site.

The system requirements page for Drupal 7 recommends at least 60 MB (disk space) for a website with many modules but does not include user created content, nor go into much detail about memory or CPU.

Is there a good benchmark to go by when measuring CPU or memory needs for Drupal projects? In my case, an early demo of the project would be fairly module heavy but only require a few pieces of uploaded end-user content.

Drupal version: