Two more I want to add as well:
1. (Which I stole from Quinton Jackson over Kevin Randleman) Get them in the clinch, make sure you have control of their head, throw a few knees and then when they start resisting to posture up and stand up straight, release them and go for the straight cross as soon as they are in the right spot.
^^ It seems to work often enough. I think people feel they weathered the storm after the knees and take a moment (that they apparently won't have) to breathe.
2. A simple combination, but effective. throw a 1-3 (jab, hook), followed by a body kick or preferably a leg kick, followed by a side kick or push kick (rear leg for both)*
*Note, faking a cross when going for the hook helps because it gives you extra power of course. Additionally, make sure you step out a good portion on the first kick. This way, you've created a nice angle for the push kick or side kick. In otherwords, move forward, move forward.. step out and kick, go into fighting stance and throw the final kick.