Hyperthreading DOES help with some non-gaming related tasks, provided they are multi-threaded enough.
For more detail - check reviews like this - http://www.anandtech.com/show/4083/t...i3-2100-tested
Note that in this review, they use stock speeds, so the 2600K will always be slightly faster than the 2500K due to it's stock speed being 100MHz faster. What you want to look out for is the few benchmarks where the 2600K is MUCH faster than the 2500K. Such as this page - http://www.anandtech.com/show/4083/t...2100-tested/19
Both are easily overclockable on air cooling to 4.5GHz or so.