I'd go for the second one .
The 280x is better than the 770
http://www.anandtech.com/bench/product/1041?vs=1037
There's a z97 motherboard that will support intel's new cpu's
There's an SSD for the boot drive , it will significantly improve your pc's performance
there's a full tower case that will allow better airflow
and there's a good psu that will provide enough power to run the system at full usage of the gpu / cpu
compared to the first one
which :
doesn't have a z97 motherboard
doesn't have an ssd
doesn't has a full tower case
is more expensive
but has :
a better gpu
http://www.anandtech.com/bench/product/1041?vs=1036
nothing else
It's your choice , i'd crossfire the two 280x's later and it will have the same performance as the...