well, I'm used to - and practice occasionally - the FAA standard, i.e. 60 degs. Here's a simple way of doing this in a 172 (all models):
DO NOT TRY THIS THE FIRST TIME WITHOUT AN INSTRUCTOR IN THE LS !!
From level flight, roll into a 30 deg bank. Now, apply one full deflection of nose-up trim. By 'one full deflection' I mean you grip the wheel at the top and rotate it to the bottom in on go - no further.
Next, roll into 60 degs. While doing so (actually towards the end of the roll-in), repeat the above trim change, if necessary 1 1/2 times or twice - this depends on the a/c, weight, etc.
Next, apply light (repeat - light!) pressure on the rudder in direction of turn to keep ball centered. Unfold newspaper (your choice) and start reading calmly. A/c will perform steep turn within +/- 50 feet (if you trimmed it right, the VSI will not move at all)). Once approaching desired heading, roll out, leading with opposite trim, as you will be well nose-up.
Great fun and actually very helpful (at bank angles of less than 60 degs, less trim) if you don't have an autopilot or GPS and need to sort out your position via VOR triangulation or just want to stay at a given height and sort out something in the a/c w/o touching the controls.