I use this computer on a daily basis for gaming, programming, and general internet surfing. It's wonderfully balanced in terms of performance. The 2500K gives me great performance for CPU-bound operations, while the 560Ti does fantastically on games. Even better is that I have overclocking headroom on both, and I could easily add a second graphics card (Albeit subbing out the power supply, most likely) for SLI.
Some pitfalls with this build: The Three Hundred is great as a case, but it does have its limits. It's small, which I like, but there's limited cable management capabilities and the fan speed controls are... Annoying. I ended up hot-gluing them various locations in the case. The power supply's P4 connector is too short to do anything but go straight there, so I'd get an extension or a different power supply. That being said, the OCZ 550W Fatality edition has served me nicely.
If I had to go back and do it all over again, I'd get a more powerful power supply (so I could build on this later). Really. That's pretty much it.