You need to download the fixed version of 3.56 here: http://www.ps3news.com/forums/downlo...o=file&id=5005
Make sure that you upgrade to that OFW version BEFORE trying to swap the drive. As far as the rest goes, I don't really think that having a high speed drive makes much difference. I have a 500GB WD Caviar Blue in mine and it works fine. It has a ton of reviews saying that it has no issues with the PS3 so that's what I would recommend.
Do not exceed 1.5 TB in size though, as I don't think the PS3 can read the 64k block size drives (1.5 TB+).