Its not just bragging rights. The 2500K offers great performance with reasonable power and thermal requirements... at a very good price. You can probably get a capable AMD system for less, but this is as good a price/performance ratio you'll get out of Intel for the near future... You're probably looking at $400 for CPU/mobo ... and add $50 for 4GB of DDR3. Not quite $600...
Most gaming reviews I've read use 30fps as the line for 'playability'. Its also a factor of image quality, graphic content, and resolution. If you can get a richer gaming experience with shinier graphics and sharper images...
I usually find the graphics card makes the most drastic difference... but the card you have should be pretty capable. Perhaps the CPU/RAM is a bottleneck. Are you playing at High Quality to get 23fps avg?