chiumiento, welcome to the forum! Sounds like you're reaching for the stars.
Nothing wrong with that, in fact on Newegg, I saw a pair of 4GB DDR3 sticks for less than $100. I paid almost that for a pair of 2GB DDR2 sticks from Crucial. The ones that I saw on Newegg, I don't remember the brand, but they were red colored, and appeared to have mini red grips on the top of them. Mabye it keeps the user from physically having to touching the chip itself, reducing the chance of static transfer.
I plan a build myself in the coming years, and when I do, I'll probably do the same. If you can get twice the RAM for less than $20 a set, it's well worth it. If nothing else, you can reduce the number of sticks that you'll need, while allowing for future expansion.
Now, many associates needing high amounts of RAM with video editing, but there are other uses where you need just as much, if not more, RAM at your disposal. I run VM's, it would be nice to be able to run two at a time, rather than just one, on a separate monitor, at full power. This would take a good quad CPU, and the more RAM, the better. If say, you run you main install, on 4GB RAM, then lend 3GB (each) to 2 VM's, that's 10GB right there, assuming that they're doing a lot of work. So 12GB would probably be ideal for me.
That's why when I do build, I want RAM, CPU & PSU to spare, in addition to a decent video card. Newegg has bundles for every need, and they also offer other combo packages at huge discounts.
It's good to see you here, and look forward to hearing from you again.
Best of Luck,
Cat