Again Thanks for your time ! It means a lot getting the first pat on your back for your work !
* I think whether a task is "Deleted" or moved to a "Completed" list or just somehow marked as completed but staying in the same list is a design decision you'll have to make. I've seen it done either way in different To-Do apps. Some people prefer the style where a completed task is completely gone and out of sight and removed from the app. Others prefer to see a log of their completed work at the end of the day (/month /week, etc). So I think it's up to you to decide what's best for your app. I would lean towards keeping the ToDo, but either marking/moving it to indicate a completion, and maybe also having a way to remove it completely.
And deciding what to do is half the fun anyway! Best of luck with it.