no, overkill now isnt always gonna be mainstream in the future.
DDR may be the future, or it may not.
the performance increase is only marginal right now.
until pc3200 ddr ram and such comes out it will have only a slight advantage over regular sdram.
Listen, if you are thinking for the future you have to realize that sooner or later EVERY COMPUTER WILL BE OBSOLETE.
I spent 700 bucks on my last computer. (keep in mind my mobo/ram were the newest technology, not necessarily the 900mhz cpu)
When you think about it, I could build a new 700 dollar computer FOUR times, once a year say, in the same cost of your machine.
I can tell you my last system will be a lot nicer than your Tbird 1.33, and since Im selling every year my components will have more resale value.
you should think about this
-Sam