Seemingly simple SQL query

I've got a seemingly simple task that I hope someone will help me with. The situation is that I've got a table with a time stamp and one or more columns with assigned data values. The question/query I need to pose is what is the value with the latest time stamp for every day and its associated value. In other words what is the value of the time stamp and value closest to 12 midnight without going over into the next day.

My attempts so far have only resulted in errors thrown by using aggregate types and I've not yet stumbled upon the correct syntax?

Thanks everyone for reading this post.

MW