Christ, any more questions all at once?

Sorry for late reply.
A lot of it depends on what you use your pc for, knowing you as I do I would say nerdy crap and multi-table grinding and no doubt you want good performance for HD stuff.
Most of the fancy shmancy stuff on motherboards is for gaming, if you basically never bother with that stuff then it shouldn't cost you too much at all.
You definitely want at least 1 Gigabit ethernet port, you'd be a full on proper retard not to get that.
As many USB3 ports as you can shake your peripherals at would be good too.
I advise including support for SSD's - I'm still undecided but if you want a dedicated boot drive that's the way to go it seems.
Decent brands include Gigabyte and ASUS, I'll even have a look for you shortly and come back with some actual suggestions.
Hard drive speed will be your bottleneck, except for an SSD.
12GB of RAM is crazy talk for your needs, unless you have some whack CAD program or something - and you probably do now I think of it.
One single decent graphics card should be fine, seriously, do you CAD from home? Might be able to recommend something that will continue to last.
One thing I've noticed with MSY is that their price list is a joke, and their customer service does not exist. Just because something is on their price list doesn't mean they'll ever actually stock it at any given store. Definitely need to ring ahead for any parts you want to order.
Back after dinner with some motherboard ideas.