I've been using some Sandisk Extreme 8GB 30MB/sec cards that I found on sale at Best Buy for $40. I haven't done video, but have done a lot of high speed continuous release, and they work great so far. Erich
SD cards measure their speeds in terms of "classes". ; Most of the ones that are on sale in stores like Worst Buy and Staples are Class 4. ; Class 4 *might* work but you would really want a Class 6 or even Class 10 to be sure you don't get any hiccups or buffer fills. ; It happens from time to time on my 5dMk2 with the CF cards that I have.
just ordered an 8 gig class 10 from amazon Tim [amazonsearch]Sandisk 8GB Extreme SDHC Card-Class 10[/amazonsearch]
The Ask Adorama podcast just addressed this subject. ; They confirmed what Tim said, a name-brand card with at least a class 6 speed rating.
I just got my D90 and I got an 8GB Extreme 3 card. It has the 30mb/s write speed and I've had no problems with it with continuous shooting. Working great so far.
It seems like the smaller stuff (SD cards, readers, filters, etc) are always cheaper online. Gotta love the interwebs.
even the big items are cheaper alot of times.I bought a canon pro9000 printer thru amazon for 409. a local store wanted 499 plus tax and then it was only available thu there web site so now we add shipping charges also and we are at about 570