As far as I'm aware, those programs do utilise hyperthreading and all those extra cores but not all that much. Personally I would go for an Ivy Bridge CPU as they should give slightly better performance than Sandy Bridge with a lower TDP and much better integrated graphics. Not to mention PCI 3.0 support, native DDR3 1600Mhz support etc. As the performance difference is quite small though, go for Sandy Bridge if it's considerably cheaper. (It shouldn't be)
Ideally you want an i7 because not only do you get hyperthreading but you get the better HD 4000 graphics as well. The HD 4000 graphics are surprisingly good in terms of performance and are able to run up to 3 monitors without an add on graphics card.
That would be great as is for your usage and there are plenty of places to upgrade. There is room on that board to upgrade to 16GB RAM, you could add a SSD and if you feel the need, a low-mid range graphics card such as the HD 7750.
Also if you care about quietness, it would be relatively easy to make this build ultra quiet. Adding the SSD would eliminate most of the vibrations as the HDD wouldn't have to spin much. If you then replaced the CPU cooler (and possibly the case fan) with something quieter (or maybe even passive) it should be close to inaudible.
A couple questions. If you aren't into OC'ing your computer, what are the benefits of having a higher quality mobo? Some of the boards I seen (like the ASUS Sabertooth) are upwards of 240$. Does that extra cost actually get you added value?
And do you think that SB processors will be cheaper now? Should I get a 3700k instead of a 3770? What about getting an i5 3500k and pairing it with a decent GPU?
I don't think a graphics card will give you much benefit unless you decide to game or maybe if you want to run multiple ultra high resolution monitors or something.
More expensive motherboards usually give more features. That could include more PCI-E x16 slots, newer tech like SATA 3/USB 3.0, better/easier overclocking etc. More expensive ones will probably cope with heat better as well.
Noone will know the pricing for sure until it's actually here but I imagine the Ivy Bridge equivalent of each CPU will be around $10 more or something. That extra bit is buying a small performance boost (particularly for non overclockers), lower power consumption and better integrated graphics. They are 3 things that you would really benefit from I think.