At the risk of getting flamed here I don't think so. I think that fast (high FSB) RAM lets you overclock more easily and with the Intel memory controllers you can run very fast RAM asynchronously to further improve performance. As for spending money to reduce latency and otherwise tighten timings, I don't think it makes any difference at all in games. It makes an enormous difference in memory reliant benchmarks like SuperPi, but for games and office applications I don't think you'll see much additional benefit.
In fact I've just bought some PC6400 OcUK Value RAM on the basis that it's £27 cheaper than the cheapest 'branded' kit and £30 less than the Geil PC6400 RAM that everyone recommends.
Why? Because I'm spending the difference on getting an E6400 rather than an E6300. Both chips will do 400MHz FSB no problem. But the x8 multiplier means that my DS4 with cheap RAM will be doing 3.2GHz at FSB400 whereas the E6300 is only doing 2.8GHz. That's why. Same money, faster. To go beyond FSB400 most Geil users have to loosen the timings off to 5-5-5-15 anyway so by the time the Geil/E6300 combination have stretched themselves up to 457FSB (3.2GHz) my choice of value RAM and a higher multiplier will still be running quicker. That's the theory. And, if by some miracle, the Eilixir chips on the OcUK value RAM turn out to be in any way overclockable, I'm well up.