How to store Bitcoin values in a MySQL database? floats are bad.... right? What should I be using to store the values of a wallet in a MySQL database?

Apparently floats are too imprecise to be storing Bitcoins, especially down to the satoshi.

So what should I be using? Decimal ?
What you want is a MySQL Decimal field.

Specifically you want a DECIMAL(16,8)

That will give you 8 digits before the decimal and 8 after the decimal

See http://dev.mysql.com/doc/refman/5.1/en/precision-math-decimal-changes.html for details.