not really.
Hyperthreading uses unused execution units, if the two programs are unrelated yes hyperthreading will have a huge impact however the light tasks of word processing and surfing is very light and you wouldnt see any difference in performance.
HT needs very heavy cpu oriented tasks to see if it makes a discernable diiffrence.
Each hyperthread is about the equivalent of 1/4 of a core. If your workload is heavily multithreaded, then the additional "mini cores" can help. It probably helps more on a dual core cpu than a quad. On balance, not much help on ordinary tasks.
depends on what you call every day usage... for me hyper threading is a necessity as my whole worked doesn't revolve around gaming. i often find im transcoding or using corel while watching a movie on my other monitor.
I'll probably wrinkle some foreheads with my comment since I've been arguing on other threads that Intel shouldn't be so stingy with hyperthreading, but according to what I've read hyperthreading gives maybe 10% - 20% boost in performance overall.
It doesnt hurt
It can only help
with modern HT cache thrashing has been reduced
No reason to turn it off
Remember OSes are multithreaded
at any given time Win7 has an average of about 500 threads running
The more threads you can process the better