I have a Canon Digi. Rebel 350D. It came with (or I bought right away ... don't remember) a 1 GB SanDisk Ultra II memory card which features 10 MB/sec data transfer. I'm looking into other cards and SanDisk is up to "Extreme IV," which is 40 MB/sec transfer (and Extreme III which is 20 MB/sec). My question is: Does anyone know what the actual write speed is in the 350D? Is it worth spending an extra $5-10 to get the Extreme IV over the Extreme III, or is the write speed limited such that the Ultra II is as fast as it can access and there's no point in getting something faster?