On the chassis, that model should work, although there may be better options out there, I haven't looked at the models vs pricing in a while. Getting a full package with chassis + expander + motherboard + SAS card would be better knowing you get matched components.
CPU load for HDD storage is pretty low, you could go for fairly low-mid range CPUs and get out just fine. Same with DRAM... 16-32GB would probably get the job done easily.
On NICs, really depends on cost versus what you need. Are you going direct attached to bypass a switch? I'd probably look at the Intel X520 or X540 NICs which are pretty cheap, and get three dual-port cards. Use one in the server and the other two in the desktops, direct attach with static IPs. If you have budget for a switch in that mix go for a Netgear model.
Do a 2 SSD combo (240 or 480GB light enterprise) for RAID1/mirror boot drives.