every time i want to rotate something, i hit ‘r’ and move in a circle. i can’t ever get something perfect like 45degrees. is there a way to just input a number of degrees?
Hold down Control while rotating to lock it to the grid. You can get pretty close like that usually, some times exact.
Unfortuantely, there is no way of setting a exact reall-life value in blender, such as degrees, inchs, meters, you name it.
But hopefully this will be added in a future release 
thanks, that will help a lot.
In Transform (Rotate, Grab, …), you can use numerical input by directly entering a number with the “normal keyboard” numbers (those not on the numpad) and the period and minus sign on that part of the keyboard. For multifield motion (translation, size), use Tab to switch from one field to the next. Backspace empties a field.
Martin
Or press N.
Yes, the numeric input is a great addition. The control key constrains the rotation to 5 degree increments and is sometimes the quickest way to get to where you want to go. That’s assuming, of course, the “where you want to go” ends in zero or five degrees (which I find is usually the case for myself).