What happens when..
The amount of tax write offs that I have is greater than my total income for the year?
I realize i will get all the tax I paid back.. but then what about all those extra tax credits, do they just go away?
Many of them will just go away. Really depends what you are considering write-offs. Some things can carry forward such as moving expense deduction, donations, you will want to use the ones that don't carry forward, and not use the ones that do as much as possible. i.e. you having moving expenses of $1000 you can claim but don't need it to get a full refund of your taxes. Don't claim them, as you can claim them in the following year.
Another one that can be carried forward is tuition credits. You can also transfer these to your parents or spouse.
Not a whole lot of help but without seeing all the details its hard to give specifics...
Another way to play around is medical expense claims. They don't have to be claimed on a calendar year, as long as they are claimed only once. i.e. you can claim from January 10 2011 - January 9, 2012 on your 2012 taxes. So as planning, you can claim medical expenses from this year on next years return if you don't need them this year. Takes a little bit of planning, and you have to keep the receipts safe until next year, but it is quite common. The key is to not enter medical expenses if you don't need them. Also note the medical expense periods cannot overlap, but they can be shorter than a year.