Once in awhile, a word seems to be in vogue among writers for the mass media (or maybe I just notice it more).  Such is the case with the word till; as in, we'll wait till the sun rises.

The writer's job is to make the most informed word choice, and though use of the word till is grammatically proper it is no match for until.  

If you are a farmer, you till the soil.  If you are a poet you cannot wait 'til your love returns.  If you are writing for the era of digital literacy, use until to join the idea of waiting to the event you anticipate.