Can someone lead us trough marketing hype and explain differences among SDHC SD cards? Now they seem differ in speed and class? Lexar markets 133x speed, Sandisk 15 Mb/s and so on. WHAT speed is enough to capture video for example? I am waiting my Canon PowerShot SD780IS12 to arrive. Thinking about 16Gb card. Had good experience with Sandisk (took more than 10 thousand pictures with 2 CF cards). Lexar gave me error messages but these were old times, might be now they improved. Also all these new brands offering cheap cards are they worth to consider?