Sandisk has been my brand of choice for CF and SD cards for years. They're not always the cheapest, but performance is top notch. They often come with a free trial of recovery software, which I have used once but was worth its weight in gold. It allowed me to recover all photos from a formatted (but unused afterwards) card.
I only ever buy my cards from Amazon as that way I know I am buying legitimate cards.
Keep an eye on the read/write speeds - faster cards are better for shooting bursts, very large files and video. They also speed up the transfer of photos onto your computer.