Agreed. Take a few steps back from this, and assume not everyone is an enthusiast. think about a few things.
I'm a government agency with about 1500 desktops/laptops. our first big cost is labor. yes our technicians are salaried, but we need a certain level of productivity to meet internal SLA's
We go with a Tier 1 OEM for our desktops, and are pretty strict about what come in the door.your choices are based on what i can support with microsoft's Configuration Manager's Operating System Deployment (OSD). using OSD, our imaging time is 1 hour. Thats all the drivers, patches, applications, everything. and the technician spends about 5 minutes to launch the process and walk away. My OEM goes as far to deliver driver packs for my OSD process. new model of their business class desktop? no proble, in about an hour, i can add support of that model in to our OSD imaging process.
How about that licensing you mentioned? are you seriously considering retail media (if your activation isnt stored in the motherboard, its not OEM)? how do you plan to manage your license keys? OEM means its in the bios and you dont have to worry too much. no keys to keep track of, or enter. You could go with an enterprise agreement, roll the enterprise edition of your OS, and either use a single MAK key or run KMS. its one thing to deal with a stick on the side of the box when you first image it, but how about 9 months down the road when you hdd craps out, and you need to reinstall your OS.
anything you bring in the door has a minimum life cycle of 3 years. our contract with OEM states everything will have a warranty for at least that, with options for 4 and 5 years as well. With that in mind, i know my end users will be down for a day while parts are being delivered, i wont get a different revision of a part that might break something else. and i dont have to worry about parts availability in general.
also, are you looking at a business class system? and is some of your hardware specs realistic? Six core I7 system for general office work isnt realistic. your HR people aren't going to care that their system gets a really high benchmark score. Can they process their paperwork in a quick manner, if so then they're happy. Try looking a Core2 system with 4 gigs. we pay about 600~700 for one with with a three year warranty.
at the end of the day, that desktop is a fixed, one time cost. however, your salary is an ongoing expense. you should look at maximizing that value. look at how well you can deliver a quality service with minimal time. If you have a good relationship with your OEM, your job gets even easier.
I may be sitting on a descent home build here at home, but at work, its a Optiplex 755 with a core2-quad and 8 gigs.