This topic has come up before. Keep in mind that no-one will even bother to look at your air ticket (to find out if it is one-way or return) unless you get pulled over for a "secondary" (translation = detailed) interview by the immigration people at the port of entry for the country you are visiting.
So, with that in mind, have a decent shave and a haircut before you fly, don't wear your favourite Che Guevara T-shirt on the flight over, and try to sort your luggage out such that it doesn't look like you plan to sleep on the street the evening you arrive.
The only reason that immigration people would give you a hassle about a one way ticket would be if you give them reason to believe that you either don't intend to leave the country, or you look like you don't have enough funds to support yourself (thus suggesting that you plan to work illegally, or go on the dole).
I travel so much for work purposes that a 48 page passport only lasts 18 months to 2 years - but I have only once been challenged to show a return ticket, and that was in Burma, where they actually check to make sure you are present on the day your outgoing flight departs.