The most efficient method for storing dates in a database?

So, I'm looking to store a date in my SQL database, and I'm not sure what the most efficient way would be. I thought of two different methods.

Firstly, people will be able to set a certain price for each day.

For instance:

March 8, 2011: $ 1

March 9, 2011: $ 2

March 10, 2011: $ 5

For my database, I thought of either storing the UNIX timestamp, or storing the month, day, and year in separate fields.

First method:

UNIX Timestamp

pros

• Only one field

against

• Need to convert date to timestamp
• You must search between start and end dates
• Search Error Prevention

Month / day / year

pros

• Easier to search

against

• Additional fields
• Takes up more space
• Will store a lot of data, which can slow down the database.

, ? ( , .)