I have two from SanDisk, an 'Extreme' and an 'Ultra II'
I don't have anything to compare them to but they seem to work well enough with my 20D and according to the specs, they should be very durable...especially the 'Extreme'.
These are listed as 'Professional' memory cards but I'm wondering if a regular memory card would work just as well. Obviously a faster write speed is better for sports & rapid type shooting but I've never filled the camera's buffer so I would imagine that regular card would work just fine for me. Uploading time may also be a factor, but I'm not usually in a hurry to do that.