i worked with a consulting firm until recently. what we'd usually do in your case is a server with a 2012 license, which gives you 2x2008 or 2x2012 VMs [with vmware esxi, but you can use 2012 hyper-v and still do 2x server vms] and run an AD/virus manager/wsus/file and print share vm and then run an SQL vm.
centrally managing logins and group policies for some basic tasks are very useful, redirecting my documents/desktop/favorites for all users so that a server backup [to a small NAS] will backup all user and server data in one shot, managing WSUS and local antivirus [for timely updates and efficient bandwidth usage] can be helpful as well as centralized printer management and file share management.
it also gives you room for growth, if you anticipate such a thing, since you can add an extra cpu and some ram/storage to a server to take advantage of down the road.
of course, thats a bit more expensive than buying a beefy windows 7 pc and just running SQL on it, but a consulting firm should be able to help get you set up, teach you a few basics [checking backups, managing users, groups and permissions]
keep in mind that the software company recommending one level of hardware for a setup will typically just suggest enough to get their software working, not enough to do much else.