Hi Sagar,
I’ve almost always traveled on one-way tickets to and from Spain, and I’ve never had a problem. However, I have heard of others who did and it does seem that on the Spanish side they’re starting to pay a little more attention to the people coming and going. I know a Brazilian guy who had to show his return ticket upon entering Spain (this was in January).
The last time I flew to Spain, I decided to be safe and buy a ticket out of Spain that I could show the guys at passport control in case they asked me for proof that I had a ticket to leave the country. I bought a one-way flight from Madrid to Geneva on Easy Jet for about 20 euros (Switzerland is a “safe zone” out of the EU—at least until November 2008, I think). The date of the flight was for about 4 weeks after my arrival in Spain. I never intended to take the flight, but I just felt more comfortable having a safety net in case they did ask for proof that I was leaving Spain. If they *do* ask you and you can’t produce a return ticket home or a ticket to another country (preferably non-EU), they can in fact require you to buy a ticket then and there. That can of course be quite costly.
I can’t tell you for sure whether this trick works, since they just let me in without asking to see a ticket out of Spain. But I don’t see why it wouldn’t. 😊