What should I upgrade?

[blaketyrka]

My build is
Cooler Master Silent Pro Gold - 1200W Power Supply

CORSAIR XMS3 8GB (4 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model CMX8GX3M4A1600C9

Western Digital WD VelociRaptor WD1500HLHX 150GB 32MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive Bare Drive

Seagate Barracuda ST1000DM003 1TB 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive Bare Drive

ASUS P8Z68 DELUXE/GEN3 LGA 1155 Intel Z68 SATA 6Gb/s USB 3.0 ATX Intel Motherboard with UEFI BIOS

Intel Core i5-2500K Sandy Bridge Quad-Core 3.3GHz (3.7GHz Turbo Boost) LGA 1155 95W Desktop Processor Intel HD Graphics 3000 BX80623I52500K

EVGA 01G-P3-1561-AR GeForce GTX 560 Ti FPB (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card

 

[hillmanant]

Depends on what your using it for? I'd upgrade the video card as I'm a gamer and do work with video, maybe a GTX 970. After that I'd get an SSD in there for faster file access.