Yes, go for class 6 IF you need your SD card for video recording (especially HD video). Otherwise, the data transfer rate is very subjective. I recommend either class 4 or 6 for your Incredible. You can find a 4Gb class 4 Micro SDHC from NewEgg for 9.99 + 2.99 shipping. It is a lot better than the class 2 micro sdhc you can find on the Verizon website!