Why should the OP get a Mac Pro then if by your own admission the OP doesn't need more than a quad-core? The primary advantage are in the dual GPU configuration, which the OP also does not need. Can you be more specific in what exactly the nMP features that will benefit the OP over something like a Mac Mini?
(Try not to be such an arrogant prick also; many of us can easily afford the nMP, but that has no relevance to what the OP should get based on his/her needs and what someone can or cannot afford has no bearing on the value of that person's advice. For the record, I'm getting a 12-core nMP. I'm willing to bet you're not.)
So I'm an arrogant prick for pointing out that quite a few here knock stuff they can't afford to make themselves feel better? Did I just do it again?...
But I guess you didn't read the rest of my message, or failed in comprehension.
My point, again, is that if the OP wants a system that will last "ten years", which i pointed out was a bit unreasonable, the MacPro, with the enhanced memory bus, solid CPUs, and overall design is the system that's likely to last him the longest.
Is it overkill for his current tasks? sure.
Will it perform better than a MacMini? totally.
Will it last longer than an iMac? most likely.
The problem is this.. the OP asked the equivalent of "I want a rock solid truck to use on the weekends" and you are analyzing the cupholder design. You are overthinking the OP request.
A MacMini might certainly serve his needs now, but a MacMini is not a 10-year system.
Actually.. for the OP.. a mid-range MacBookPro might be a good choice. Or if the system can be a tax-write-off, then an iMac might be ok too, with the expectation of replacing it every 3 years.
But again, I will chuckle at all the folks that rage when someone "who doesn't need a MacPro" wants to buy one. Jealousy is the only reason for that.