unlike the above repliers; i will give you a serious answer.
i own an old new orleans style "shotgun double" house, which is two 900 sq ft otherwise separate houses, except they share the same inner wall.
i found two problems with the "living on one side and renting out the other side" concept:
first off, dealing with renters. otherwise normal appearing people can turn into demanding, pithy, late paying, interior destroying azzhoals over the time of a 1 year lease.
hiring a property manager was the best thing i did. for 10% of the rent, she advertises the vacancy, screens potential renters, collects the rent, has minor repairs done, and deals with all those strange azzhoals.
second issue: noise. this house was built in 1911, no isulation on either side of the common wall. i could literally hear them next door boinking, coughing watching tv, even talking loudly.
i suggest you make sure any house you buy is well inusulated.
the income tax deductions are awesome. any receipt that vaguely resembled a house item was saved for income tax deductions, any improvements that i made on either side was "wrote off". my tax refund was anywhere from 2 to 4K higher each year.
i would also suggest that you make sure you have plenty of personal liability insurance on you and the property...there's no telling what some devious tenent would try to sue you for in today's litigation-prone world.