Thanks for your question.
Unless you are filing single or filing married separate, your gross income of less than $12000 (excluding non-taxable disability) is lower than the minimum filing requirements for a tax return. Each year the minimum gross income amounts change slightly. You can check if you need to file by looking at IRS Pub. 17 each year under "Do I have to file a return?" For 2009, see http://www.irs.gov/publications/p17/ch01.html#en_US_publink1000170388
You would also want to file a return in future years if your income increases or if you wish to claim refundable credits. To answer your question, you do not have to go to a tax preparer (like H&R Block) if you have determined for yourself that you do not have to file unless you feel more comfortable in doing that.
Hope this helps,