Agree w/ putting on a new roof.  My old roof was iffy when purchased, and leaked 2 years later (fortunately it leaked right over the bath tub, and we were planning on redoing the bathroom anyway.  

My brother and I stripped off 3 layers of shingles, and then reshingled (luckily the sheathing was fine).  Total cost in materials, new gutters, etc... was less than $3000 (my quotes were around $10000, mainly due to stripping the old roof).  Along the way I learned how to shingle (my brother had done it the previous couple of years), picked up some good ladders, and saved a bunch of money (which then went into a new bathroom - I can't stand contractors now, BTW).

Sam