Mentalist is correct on the sound card thing, unless you are an audiophile (or want a whole bunch of things connected to audio at once, some dedicated cards have extra ports for fancy set-ups), don't bother with a dedicated.
CPU
Intel has been the best option for CPUs for a while now, so I would recommend them. If you can spare the cash, get an i7. Is it necessary? No. Will it help? Yes. Either way you don't want less than an i5. As you are getting a new computer, definitely get a 4000 series. So if an i5 get the 4670, if an i7 get the 4770. The 4000s aren't a big improvement over the 3000s, so if you already have a 3000 it's not worth updating, but if you are getting a new one there is absolutely no reason not to get a 4000. They are still better, even if not much, they cost about the same as the 3000s and they use the latest CPU socket.
So if you get a 4000 you'll want an LGA1150 CPU socket on the motherboard. As you are doing gaming, you will want the motherboard to have the Z87 chipset.
If you don't plan to do your own overclocking, don't bother with the CPU version with the K after the number.
RAM
Don't bother getting anything with a faster clock speed than 1866MHz, 1600MHz is also fine. If possible, get a C9 (also occasionally listed as CL9). This represents the Cas Latency, the higher the number, the worse it is. C9 is generally the sweet spot for price vs performance.
8GB is fine, but sometimes it's not much more to get 16GB, which certainly won't hurt (if you have multiple monitors and like to do lots at the same time it'll help more). Pick clock speed and CL over amount if you are happy to add more RAM later (when adding RAM always make sure all RAM has the same CL and clock speed, preferably get more of the same range of RAM, though they can be different amounts).
Next decision is how many sticks. The more sticks you spread the same amount of RAM over, the more access your computer has to that RAM. However, using fewer sticks allows room to just add more RAM later by getting some more sticks without having to replace any. It's basically a question of 4 sticks vs 2. if you are getting 16GB it'll serve pretty well for quite a while, so you could go with 4x4GB instead of 2x8GB. If you're only getting 8GB, make it 2x4GB.
SSD/HDD
Realistically, you can install the OS and basic programs on your SSD and install all your games on a secondary HDD. The place you will notice the most improvement by using an SSD is the with the OS, especially boot times (programs on it -including games- should launch, save things and install quicker, but games probably won't run much faster in general play). If you have a couple of higher end games that you know you will play a lot, no harm in installing them on the SSD, just keep in mind you don't need an SSD big enough for all you games and programs. Just enough for the OS and whatever high-end software you want to run often (fancy games, editing/rendering software, etc).
GPU
Okay, important question: Do you plan to SLI/XFire? (use two graphics cards)
The answers to those will determine your GPU.
If yes, Nvidia has the cards that get the most out of being used together. If no, you can get better high-mid range bang for buck from AMD. Either way, I would go higher than that example card. For AMD for example, grab the HD7970.
I haven't heard anything about needing to pair AMD-AMD or Intel-Nvidia.
Anything else, like mobo, PSU and case is largely determined by above choices.
Mobo needs to be compatible with the RAM, have the CPU socket you need and the chipset you want. Some may come with other useful features. One to keep an eye on is the number of USB ports and eSata ports. They'll all have good audio, and ignore onboard/integrated graphics.
PSU needs to be powerful enough for CPU and GPU/s, and keep an eye on the
80+ rating. This is a third party power efficiency rating, the better the medal, the better the efficiency. Better an 80+Bronze than one without an 80+ rating.
Case, make sure it fits everything, taking particular note of the length of GPU and how much space that bit has in the case. Other things to keep in mind are the front ports it has, what sort of cooling it has and if it is sound dampening. For cooling you want nice flow-through for the air, not necessarily fans all over the place. Keep in mind the cooling when you try to hide the tower as well, make sure air can flow properly. If it's a dodgy spot, water cooling could help, but I've never found it necessary when the case has good access to air.