Hi, guys. Figured it'd be best to start a new thread to get some of these questions answered before I drop a load of cash on this stuff.
 
SO I'm curious- when it comes to RAM, would getting more be anymore helpful even if what I'm doing now is barely topping out at a little over half used?
In addition, how *big* of a performance difference would I get if my computer is running dual-channel mode on 2 pairs of 2gb sticks rather than 1 pair plus a 2gb and a 1gb stick? 
Finally, would it be of any bad consequence if I used, for example, a pair of 2gb sticks together with a pair of 4gb sticks? (4 slots, 12gb. Seems to be that people usually have 2, 4, 8, 16, 32 etc. , but never f.ex. 10, 12, 24, etc)
 
Also - any good tutorials on replacing a socket processor? This is my first time doing it and I want to do it right!
And where can I buy those static strips so that I don't destroy everything while working on it?
 
Thanks, guys. I thought I was somewhat tech-savvy, but really there's a LOOOT I don't know, especially when it comes to hardware.

More RAM will not help anything until you start to use it. If you are not using what you have installed performance will not improve by adding more. You need to consult your motherboard documentation, but generally installing matched pairs of RAM in dual channel sockets will give you some speed improvement, although not doubling it as theory might suggest. If your RAM sticks are not matched, ideally same brand and model or at least identical specs, then you usually will not get the dual channel to work, or the speed will default to the slowest module. On most motherboards you can install two different sizes of memory to two different dual channel pairs and they will both work dual channel, for example if sockets 1 and 3 are a pair and 2 and 4 are also, you can install 1 MB sticks in sockets 1 and 3 and 2 MB sticks in sockets 2 and 4 and everything will work dual channel. 
http://www.gamersnexus.net/guides/1349-ram-how-dual-channel-works-vs-single-channel?showall=1
 
 
Installing a socketed CPU is pretty straight forward, and the instructions typically can be found online it they are not in the box. Removing an old CPU can be problematic if the heat sink compound/thermal paste has hardened and sticks the heatsink to the CPU. The release lever for the CPU is typically inaccessible under the heatsink and removing the heatsink can potentially pull pins out of the socket rendering the old CPU unusable, and in the worst case leaving a pin stuck in the socket that might prevent a new CPU going in. If the heatsink sticks, warming it may help. I have assembled dozens of static sensitive parts in computers over the years without using a static strap and never had a problem. Grounding your hand to the chassis prior to handling the part is wise, and you can make an effective ground strap if you are worried just by wrapping a bare wire around you wrist and attaching the other end to a ground.

david has lots of good info there, here's some more thoughts:
the biggest boost from increasing ram happens when you go from 4 to 8 on a x64 win box, which gives win enough to avoid paging, above that it really depends on the apps you use...
buying ram in matched pairs is still considered worthwhile (i think, maybe i'm out of date)...
there's lots of youtube tutorials on swapping cpus out...
you don't necessarily need an anti-static band - if your box chassis is earthed you can discharge via that before doing anything...
hth, good luck, have fun!

RAM does not speed up the PC, a common misconception.  There may be a very slight speed up if Windows can "cache" something in RAM instead of the hard drive but that's all.  What more memory does do is allow more programs to be opened at one time. 
 
CPU "sockets" are very fragile and if pins in the socket get bent in most cases the motherboard is junk.  Before buying a new CPU, make sure the motherboard you have will accept what you want or even if it will accept an upgraded CPU. 
 
If you finally decide to replace the CPU, carefully remove the CPU cooler with the PC warmed up as its easier to separate the cooler from the top of the CPU.
 
I'm from the old school, I have a grounding wrist strap that I use as I believe in "Murphy's Law".