Which DVD-R standard? That I'm not too skilled with, I haven't played with them. So I'll throw that question out to the audience...
Seriously, though, if you have a 12x and it works fine, then don't worry. I bought a 24x about 3 months ago and was terribly disappointed at the speed. Exponentially, you are not saving that much time. A 12x can do a disc in about 6.5-7 minutes. A 24x does the same in 5-6 minutes. It doesn't make a whole lot of difference.
I'm guessing with the way DVD-R prices have come down in the last year, and that it is an emerging standard, that we should see drastically lower prices by Christmas or into next year this time. Think about CD Burners when they came out. My friend had a 1x burner that cost him like $800. I bought a 2x a year later for $200, and 8x six months later for $150, a 12x a year later for $95 and a 24x six months later for $70. I just bought a 32x for $30 (after rebate) and only really bought it because it was so darn cheap...
--Christopher