First off: you don't have to do your 2010 taxes before you do 2011. Get 2011 done first and on time, then do 2010 as soon as possible. The deadline to get 2011 taxes done is April 17, 2012.
Next: totally second Turbotax. I'm studying accounting, and I have taken one course on tax preparation; Turbotax is really easy and just as accurate as any tax preparer for most people. I use Turbotax online for free - I just get all my W-2s and other "Important Tax Information" together and answer the questions, kind of like taking a survey. Turbotax figures out what forms to file, checks for deductions, and fills all required forms out automatically. Turbotax did my student loan interest deduction for me too. This year I have a refund coming, so I entered my bank account information and it should be direct deposited soon. You can pay also, but it sounds like the free or Basic version will work for you.
I would say try Turbotax for your 2011 taxes first and see how that goes. It doesn't file until the very end, so you could go through the whole thing and not submit at the end if you're unsure. It will give you the option to look over all the forms, and you could even print them out and take it with you to the tax place if you want a second opinion.
It's totally worth it to pay for someone to do your taxes if it helps you get them done and avoid the IRS penalties and fees. If I was going to pay, I would go to H&R Block or find a local CPA firm if my situation was more complicated (small business, lots of investments, etc.). Also CPAs can give tax planning advice - not sure if tax preparation places do that. I'm sure Liberty Tax Service is fine, but their marketing just grosses me out.
The key with getting your taxes done is to keep all your documents together and make an appointment for February or March. I think some firms will schedule you for the next year and give you reminder calls before that appointment - probably not the tax preparation places, but the CPA firms will.
FYI about deductions: You can deduct student loan interest (or at least a portion of it depending on your income) when calculating your AGI on the 1040A return, using the worksheet in the instruction book - or have Turbotax or the tax preparer do it for you.
However charitable deductions can only be taken if you itemize instead of taking the standard deduction after you calculate AGI. The standard deduction will be $5,950 (single) or $11,900 (married filing jointly) for 2012. You would have to donate more than that in 2012, or have other payments you can itemize (mortgage interest, real estate taxes, sales tax, large out-of-pocket medical/dental expenses) that total more than the standard deduction to benefit from that.