I understand the whole principle behind giving something up for lent. My parents gave up alcohol every lent. As a child I usually gave up candy. It is a way to show your understanding of the sacrifices Jesus made. However, who does it really help? As soon as lent is over, you go back to doing what you did before, you haven't improved yourself. My personal opinion is that it is an empty tradition that most people don't think all the way through.
If you are going to give up something for lent you should give up something that is both difficult for you and betters others or yourself. For instance, give up smoking, and do it with the expectation that you will not pick up the habit after lent.
Rather than take something away from your life during lent, it is better to add something extra to your life that is difficult and enhances the life of people around you. For instance, make a pledge to volunteer your time on a daily basis to a charity. Or, even something as little as paying closer attention to your attitude and making an effort to be positive around everyone, especially those you do not like or do not normally talk to. Do you see a homeless guy everyday? Pledge to make a difference in that guy's life even if it is only for 40 days during lent.