I've always done my own taxes since I never get back enough to pay a professional. First starting, I used TurboTax, but found it to be waaaay too complicated for what I was doing. Now, I just sit down with the paper ones...so I can make mistakes, then go online and type it out.
I will say, I've had some pretty crazy taxes before. One year, I was self employed (oh yeah...that's a FUUUN one), had social security paychecks (another FUUUN one), tuition, business expenses, itemized deductions, etc. It was horrible, but I still managed to do them on my own.
It really depends how patient, calm, determined, and good with simple math you are. If your time isn't worth it, pay a pro (Like Slicktrax!)