If you are looking to purchase a home anytime soon, I would strongly advise you NOT to pay off anything that is identified as a collection, write-off, or judgement on your credit report before you talk with someone who is proficient in analyzing your credit as it today.
These are classified as "Derogatory" items on your credit report so when you make payments on these items to pay them off with one payment or to make multiple payments over time, every time there is an activity updated on a Derogatory item in your credit report, it LOWERS YOUR SCORE, even if it is a positive action such as paying down or off your debt.
There are strategies involved to position you in the bst light for when you are ready to apply for a loan. You can be ready to be approved for your loan soon, or if you do the wrong thing, it could be much later after your score heals over time.
Check out: http://www.trulia.com/voices/Home_Buying/Can_anyone_tell_me_how_long_it_takes_for_a_FICO_sc-143604
I am happy to answer any question you may have.
All the best,
Roswell Moore, CMPS
Certified Mortgage Planner