I'm gonna be in the market to get a new computer in the next few months, and I want to get a custom built one but I have no idea about the differences in the specs, what I'm shooting for is that it's able to play a game like Napoleon: Total with NO problems, and still be able to be compatible for a couple of years. Thanks for the help in advance if you help.

You want something to last and not bottleneck you, go intel. There isn't alot of upgrade paths for amd stuff, except the X6 phenom which has more cores with less horse power. Lots of cheap ati cards these days that are very powerful. I can't recommend anything because I don't read ati benchmarks because I don't use ati cards.  
 
Then again you can be fooled into getting a X4 phenom and think it's good enough, while your at it, why not just get a crossfireX mobo? I recommend a LGA 1156 mobo or intel X58 mobo instead, which I use. I can crossfireX or sli anything with it if necessary. Honestly lot's of ppl might say get an i5 or something like that, or it's good enough ect. Just do what I do, get an i7 if you want less bottlenecking, alot of power and to last a few years. Sure it may cost more, however you want something that you don't have to upgrade for a few years. Of course the videocard, you will have to change it eventually if you want it to last.