dont buy the xbox 1, for $600 you can build a decent gaming rig minus the peripherals, and even then you can get a cheap temporary mouse/keyboard for $20 together and use a hdtv temporarily as a monitor! if you could come up with $800 for the gaming rig w/o the peripherals, this would be a really nice build..
CPU: intel i5 4690k ($217 @ microcenter)
MOBO: asrock z97 extreme4 ($76 @ microcenter)
MEMORY: corsair xms3 8gb (2x4) ddr3 1600mhz pc3 12800 ($72 @ newegg)
STORAGE: seagate 1tb sshd ($75 @ ncixus)
GPU: asus nvidia gtx 760 2gb ($230 @ newegg or ncixus)
CASE: diablotek evo mid tower atx ($43 @ microcenter)
PSU: corsair cx750m 80+ bronze certified ($65 @ ncixus)
DISC DRIVE: asus 24x dvdr/rw ($17 @ microcenter)
TOTAL: $795
you could sub the gpu in this rig for a 650 ti and that would save $90, could get a lower powered 600w psu for $30 less same brand, could save $25 on the sshd by going with a hdd instead, all that would put you at $650. if you really got desperate you could go with 4 gb of ram for now instead of 8gb, save yourself another $30 ish, thats an easy add on later to add 4 more gb, and 4 gb is plenty for most gamers anyways.