Well, I believe the Bible is the true, inspired Word of God.
Where I think problems come in is in our ability to interpret what God said. So, I accept the Biblical account of the flood as a matter of faith.
Bottom line is though, it's not really about how much water there was. The points to take away from the story of the flood are:
1) God is looking for His people to be faithful and there will be judgment for those who are not.
2) Noah "found grace in the eyes of the Lord." Noah was faithful to do what God commanded in spite of being ridculed.
3) God gave the promise through the sign of the rainbow that He would not destroy the earth in that manner again.
Having said that, whether all the animals got on the boat, whether that's how the dinosaurs were wiped out, whether the flood covered the entire globe, how Noah got all them critters in the boat are interesting parts of the story about which we can speculate.
Thanks :~D Something to ponder :~D