the trouble with pre-built or built to spec systems is that they all use crappy power supplies to keep costs down.
however cyberpower pc have improved the power supply options a lot - however there have been a few complaints about packaging and shipping, but annoyingly they are the best budget to performance custom pc builders:
*BASE_PRICE: [+495]
BLUETOOTH: None
CABLE: None
CAS: Thermaltake Urban S21 w/ USB 3.0 & Side-Panel Window [+4]
CASUPGRADE: None
CD: 24X Double Layer Dual Format DVD+-R/+-RW + CD-R/RW Drive (BLACK COLOR)
CD2: None
COOLANT: Standard Coolant
CPU: Intel® Core™ i5-4460 3.20 GHz 6MB Intel Smart Cache LGA1150 [+124]
CS_FAN: Default case fans
DOCKINGSTATION: None
ENGRAVING: None
ENGRAVING_MSG:
FA_HDD: None
FAN: Intel Certified CPU Fan & Heatsink [-27]
FLASHMEDIA: None
FREEBIE_TB: None
GLASSES: None
HDD: 1TB SATA-III 6.0Gb/s 32MB Cache 7200RPM HDD (Single Drive)
HDD2: None
HEADSET: None
IUSB: Built-in USB 2.0 Ports
KEYBOARD: AZZA Multimedia USB Gaming Keyboard
MB_SRT: None
MEMORY: 8GB (4GBx2) DDR3/2133MHz Dual Channel Memory (ADATA XPG V3)
MONITOR: None
MOPAD: None
MOTHERBOARD: ASRock Z97 Pro4 ATX w/ Intel GbLAN, 2 PCIe x16, 2 PCIe x1, 2 PCI, 1 x M.2, 6x SATA 6Gb/s (All Venom OC Certified) [+37]
MOUSE: AZZA Optical 1600dpi Gaming Mouse with Weight Adjustable Cartridge
NETWORK: Onboard Gigabit LAN Network
NFC: None
OS: Microsoft® Windows 8.1 (64-bit Edition) + Office 365 FREE 30 Days Trial [+104]
OVERCLOCK: No Overclocking
POWERSUPPLY: 750 Watts - EVGA SuperNOVA 750 G1 80 PLUS Gold Power Supply [+56]
RUSH: Standard Process Time: Ship within 10 to 15 Business Day
SERVICE: STANDARD WARRANTY: 3-YEAR [3 Year Labor, 1 Year Parts] LIMITED WARRANTY PLUS LIFE-TIME TECHNICAL SUPPORT
SOUND: HIGH DEFINITION ON-BOARD 7.1 AUDIO
SPEAKERS: None
TEMP: None
TUNING: None
TVRC: None
USBFLASH: None
USBHD: None
USBX: None
VIDEO: XFX Double D AMD Radeon R9 280 3GB GDDR5 PCIe 3.0 x16 Video Card [+125] (Single Card)
WNC: None
_PRICE: (+918)
that was a quick config I came up with. it includes a new mouse, keyboard and OS, but not a screen.
edit: if you want a monitor in that price, downgrade the I5 to an I3, and the motherboard to the b85 option. that way you've still got the 280.