I would suggest to purchase all systems from Dell. it would save you from lot of headache..
Vostro 220 matches your requirement and starts from 26.5k.it work out a look better deal for you because of following reasons:
* Onsite support and warranty for complete PC, In business who has a time to chase separate hardware vendors for RMA?
* Preloaded licensed Software (OS & Antivirus)
* Sleek look and aesthetics of the machine
Their prices are little above your budget but it isn't a bad deal considering the you are getting more value. also, if you are getting multiple units, little negotiations can be done with dell reps and prices can be reduced.
I had worked on these machines in my previous workspace. nice sleek desktops!