You seem to have it more or less sorted. You do say, is it worth the $$, yet you dont give us a price that it costs, and a budget that you have! To be honest its probably worth it anyway as the rig will be nice for gaming, and you generally save a little when you buy / build yourself.
The only thing you should be wary of really is re-using your old case. If you say its currently a MATX, then you should be wary about putting a normal ATX board in there. The measurements of the new board are: 12.0" x 9.6"... Also, check the pins / adapters of the new board, and that they are going to fit into the current holes of your case (theres plenty of pictures on the site you're buying off) Bear in mind as well you wont want a MOBO (motherboard) that JUST squeezes in, you will want to leave space for cable managment and good airflow.
The CPU is a nice gaming processor, its the black edition, which means, in this case, the multiplier is unlcoked. Basically with 'overclocking' you change the base rates of the CPU in order to gain more 'power' (GHZ).
The base rates are based around the FSB (front bus), the voltage, and the Multiplier. As you recieved a normal CPU (for example yours) it comes at 3.2GHZ stock speed. it might be running at X amount of volts (lets just say 5volts) and the multiplier is at '1.4'.
You can go into BIOS settings (or sometimes use software) and say ''Processor, run off 6 volts, and the multiplier, run at a 1.5 multiplier'' then your speed of the processor might go up to 3.5GHZ. You can get those sort of processors up to 4GHZ pretty easily, and probably on standard air cooling! However be careful when doing it, as you can do damage if you have no idea what your doing.
(theres plenty of posts on this forum about overclocking)
Yeah, using dual channels for the RAM is better than using the one, GENERALLY, as you can split the load the RAM has between 2 different slots, rather than pilling it on one. As long as you have the same type of RAM in both slots you're good to go. (yours is fine, DDR3 is newest / best technology atm for RAM, you might want to upgrade an extra 2GB/4GB in the future, but atm, your fine)
The specs on your MOBO, just tell you what you can use with it (Slots for Drives, Type of RAM, etc) The features, you can read up on, but anti-surge fairly self explanitory, TurboV off the top of my head routes CPU power to where its needed most (basically internal intelligent resources distribution)
Think thats roughly it - shout if you want more info