The newer generation of CPU's are not only focusing more on energy efficiency, but performance per watt
Currently, Ivy Bridge is only available on LGA 1155. That will soon change with Ivy Bridge-E on socket 2011.
There are 8 'core' offerings from AMD at the moment. They are the FX-8150 and FX-8120; AMD will soon release two more offerings with the new Piledriver architecture later this month - AMD FX-8350 and AMD FX-8320.
There are also 8-core offerings from Intel as well, however, you will have to spend large amounts of $$$ to purchase Xeons.
And last, no, there is no way in heck you will need an 8 core CPU to do the tasks you listed. Right now, a Quad-Core (without Hyperthreading) is MORE than enough for the tasks you listed. Heck, even an i3 (Dual core, Hyperthreading) is considered enough for gaming!