Since the Stratocaster does have three pick-ups you may like the idea of swapping any of those single coils for one single coil size humbuck pick-up.
Single coil size humbuckers do have the advantage of having the same size as your single coil, no need for extra routing in the body of the guitar to make the humbuck fit.
Companies like Dimarzio and Seymour Duncan do a large range of single size humbuck pick ups. I mention those two names as they seem to be popular and therefor easy to get hold of.
Once you have installed your humbuck (either neck or bridge) you will notice the difference straight away between the humbuck sound and the single coil sound: The humbucker will sound a tad duller but also fuller when used with a clean guitarsound. Switching between the humbuck and single coil will let you experience the difference between the two different sounds. You will be amazed how bright single coils sound. They can still cut through in the mix, but their sound is sharp and bright.
Using distortion (or gain) on your amp you will find that the humbucker will be smoother and softer in sound. Yes it will give you that singing sustain, even on a bolted on neck Stratocaster. This may be a fun experience if you are used to Les Paul type of guitars to get you that kind of sound.
Once you have installed one humbucker you may even like the idea of installing another one, either in bridge or neck postion, depending on where you did put your first humbucker.