Office systems, approx $500 budget

Lookin to setup 3 almost identical systems for an office, $500 price range, data entry with multiple memory intensive programs running on dual monitor. One system is doubling as the server for the main program (WinTotal, appraisal software that at times can be very cpu/memory heavy) and the man wants it a bit beefier. (Was planning to add 2x the memory, as the cpu should be overkill already) Their current systems are occassionally bogged down by terrible processing/loading lag, however they are older (5...ish year old) systems. Should be able to scrape by with the onboard video, as the systems will not be used for gaming.

Case: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Mobo: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Memory: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Opticaldrive: http://www.newegg.com/Product/Product.aspx?Item=N82E168...
Vid card: Onboard
Combo:
Psu: http://www.newegg.com/Product/ComboDealDetails.aspx?Ite...
Hdd: http://www.newegg.com/Product/ComboDealDetails.aspx?Ite...
$493, including $15 shipping. Also, since there will be 3x everything purchased, NOT counting rebates. (Not that they are ever received, anyways...)
-edit-
OS: Have 1 win7 ult, 3 home premium licenses for use

Case was chosen as space is at a premium at one desk, its cheap, and I've used that one with success in a prior build for my wife. Possible alternatives for the 'main' system, as that one is able to be budgeted at up to $600
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
http://www.newegg.com/Product/Product.aspx?Item=N82E168...


Been looking at the best config polls, and newegg till my brain turned to puddy... Appreciate any tweaks/compatability issues/etc that you guys can see, as I'm now well past the burned out stage and this, like everything else, needs to be done by yesterday.

Purchasing off Newegg or Amazon(Have prime for the 2day shipping)