Try to avoid decaf unless it is filtered by water. Best bet is buying it from a coffee shop. Gloria Jeans has good decaf.
There is a tea called Rooibos, it is south african and is caffeine free. Not sure it will keep you awake, but is' nice and good for you!
I have a coffee every second day or so, don't worry too much if you have a little caffeine. There are also coffee alternatives such as dandelion tea. Check the ingredients first, but you can find them in the coffee section of the supermarket.
Green tea has a fair bit of caffeine too, but one or two a day is still within with recommended limit. Make it weak as well, and it will be fine. xo