I just got a dell inspiron 1501, which appears to support up to 533mhz DDR2 ram. it's a turion TL-60, and I'm not actually sure what the FSB is (been a while since I've followed cpu news). I'm looking to get a couple of 1gb sticks of ram, and at newegg right now I can get 2 transcend 1gb 667mhz, cas latency 5 sticks for $66, or 533mhz, cas latency 4 sticks for $70.

is it worth the extra $4 for the lower latency? obviously not a lot of money, but I'm wondering if there's any actual performance difference, or if it matters if I'm using 667mhz that's running at 533mz speed

Save your $4, the lower latency won't matter (especially since you're running at a slower speed than it's rated). In fact, usually if you run RAM at a slower bus speed than it's rated then it can go at a lower latency. But that's only with an overclocker's motherboard, your laptop will just detect the speed and use it from the SPD info on the memory.