You say tom-a-to, I say tom-ah-to.  But the income driven repayment options are much more different than their names imply.

Pay As You Earn (PAYE) gets you the lowest payments and earliest forgiveness, but can't be chosen by people who borrowed before October 1, 2007.

Income-Based Repayment is a little more expensive than PAYE but is available to more folks.  

Income-Contingent Repayment isn't the newest or cheapest option, but if you are a Parent PLUS loan borrower, it's the only available income-driven plan (and only after those Parent PLUS loans are refinanced into a Direct Consolidaton Loan).

Your options depend on:

Income Contingent	Only Direct loans No Partial Financial Hardship required Not available for Parent PLUS loans Available for consolidation loans that repaid Parent PLUS loans
Income Based	FFEL and Direct loans Partial Financial Hardship required Not available for Parent PLUS loans Not available for consolidation loans that repaid Parent PLUS
Pay As You Earn	Only Direct Loans Partial Financial Hardship required Not available for Parent PLUS loans Not available for consolidation loans that repaid Parent PLUS No balance on a federal loan as of Oct. 1, 2007 Must have a federal loan on or after Oct. 1, 2011