My favorite moves are also the ones that are the most strenuous on my lungs. But there's something about them that I love:
1) Kickbox moves in a step routine (that last step routine in Lowmax just rocks -- it takes the breath out of me, but it ROCKS!)
2) Step slams
3) Power 3's, 7's and 15's (again, they blow me away, but I love 'em).
4) Triples around the step are okay, as long as they're not excessive.
5) A-steps
6) That modified triple hop repeater in Rhythmic Step (I should move this up on my list, because I really like this move)
A lot of times, my favorite "moves" are actually combinations of different moves. Some combos just come together to be more fun than others. For instance, that last combo in Step Blast just brings a smile to my face, as does the entire last combo in Rhythmic Step. Each move by themselves isn't "all that", but when you put them all together, it's great!
EDIT: I also like:
Pendulums
Fast foot repeaters
Reverse Mambos