You can spend over $2500 on just the monitors. That said, with your budget I would probably spend about $1500-$2000 on the PC and $300-1000 on the monitor(s). Absolute minimum 8GB of RAM (16GB better), You should go with 2560x1440 or 25560x1600 for the monitors although 1080x1920p can keep the costs of the monitor down. Also get at least 200GB of SSD and a 2TB HDD for mass storage will not hurt.
Mid range PC is $400-800. High end is generally $1000-$3000 (and more). If you are looking at over $2000 for just the PC (no monitor), then you tend to be getting into more server class, probably with Xeon CPU(s) and ECC memory designed for 24x7 operation, etc...
The more you spend, the quicker it depreciates. For example, you might want to consider spending $1250 now (ie: $1100 for PC and a $150 monitor), and in 3 years buy another PC for $1250. Chances are, in 3 years you will be able to get a better PC for $1250 than you could today for $2500.








