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Dell and HP have the Intel Haswell i7 chip. Desktops Dell 8700 forget the HP model usually on there for $600-700.

Advice going to a SSD boot drive is good they are crazy cheap now 250GB. A mechanical HDD will be the slowest thing in todays PC. Win 8.1 will recognize the new the 4 terabyte + backup drives.

Windows 7 is going into maintenance mode next month. No new feature updates.    

So add a 256 SSD and a mid range video card ~ $100-200 to drive the multiple monitors. 4 monitors I believe require Displayports so match the video card to the monitor inputs. That super wiiiidddeee monitor looks a little funky as it is not very tall for documents and spreadsheets compared to a pair of 27" FHD 1920x1080's.

Spend the most money on the monitors:  matte finish eliminates any screen reflections and glare, IPS gives well lit wide angle picture perfect minimal eye strain viewing.      

Another concern is stepping up to business class desktops. With rampant Identity theft happening what is coming down the road is multi-factor authentication and encrypting everything. The business class chips and Windows 8 Pro accommodate this feature in a hardware TPM module.

http://en.wikipedia.org/wiki/Trusted_Platform_Module

note: be aware that video cards take more power than cpu's these days That Haswell i7 may be 86W but the video cards can spike 100's of watts requiring a larger power supply in the box. And everything has fans to keep the temps down it may be more noisy than that 3 fan xp box.