Income limits for deducting qualified student loan interest need to be increased.
The current limit on MAGI (Modified Adjusted Gross Income): $150,000 if married filing a joint return; $75,000 if single, head of household, or qualifying widow(er).
With the increasing costs of education, most people are required to take student loans to complete their education. Education in most cases causes a person's income to rise, thus creating more taxable income over time.
For comparison, the mortgage interest deduction is not subject to limits on MAGI but is instead subject to maximum debt limits.
http://www.irs.gov/taxtopics/tc456.html
http://www.irs.gov/publications/p970/ch04.html
http://www.irs.gov/publications/p936/ar02.html#en_US_2011_publink1000229991