Looking to upgrade build

[oldcomputerhardwareguy]

I'd like some input on an upgrade I'm considering, as I haven't paid much attention to hardware since I got my last machine years back. My current build- I can't even remember most of the parts- is:
Athlon X3 450
BIOSTAR motherboard
12GB DDR3 (2x4GB, 2x2GB)
GT 630 2GB GDDR5
1TB 7200RPM HDD
Antec ATX Mid-tower
400W PSU
I want to upgrade into two machines, one as a computer for my wife/kids (web browsing, minecraft, etc.) and one for me, which will be doing video transcoding, video editing, virtual machines, and server work, along with working with C++, JavaScript, XSS and HTML. I will need one monitor, 1080P IPS of any sort. I was thinking of a Mini-ITX Athlon 5350 build for wife/kids and an Athlon X4 860K for me. My stuff is already on Linux, and wife/kids are using personal copy of Windows 7 Home Premium (not OEM). Should be ~400 dollars, and I prefer AMD but will use Intel if it is a better choice in terms of price and performance. Thanks in advance.

 

[jerdle]

Question needs to be reworked - are you asking what you can upgrade the build listed above to for $400?

 

[MasterDell]

A 5350 is pretty horrible I will let you know that haha. It isn't terrible though I guess. Just make sure it's OS is on an SSD. I've gpt a 2650 build which I built in a wooden case using 1x4gb of RAM, a 350W(I think) Seasonic PSU, and an old 2.5" HDD which had been used in an old laptop for atleast 5 years. It's running Ubuntu and its only job is to be quiet and run Old School runescape while I sleep. It works better than you'd think.

Kid's/Wife's Build: http://pcpartpicker.com/p/vptbgs

Your build: http://pcpartpicker.com/p/fmnrgs

Only thing that worrys me about these builds is that your GPU might not be powerful enough. If the 630 was good enough before, then the 740 will definitely be good enough.