No, I won't buy the pet but that's largely because I'm not that interested in it. I don't care one way or the other about store pets/mounts. Never did and certainly unlikely to change my mind now that you can get them with gold.
As for the charity angle, I would prefer that Blizzard picked two or three local charities in Houston and Florida and gave us a choice where to direct the funds. The Red Cross, despite their best efforts, is inefficient due to their size and national bureaucracy. That's inevitable. I don't think they are evil. I just believe that local established local charities do more with less. The Red Cross is an easy choice and I support them through twice-a-year blood donations but I do believe that there are better local choices for disaster relief.