I have reason to believe that a lot of my readers also read Tmuscle, but in case you haven't seen it, check out this article on fat loss: it's a summation of what a baker's dozen of the best strength and conditioning coaches currently out there have to say about the best workouts for slicing blubber off your body. And since fat loss is the hottest topic out there--always--and these guys (they're all guys) make their living from this stuff, it's worth a look.

If you're really short on time, however, you can just refer to the Cliffs Notes version I've created below. Listed are the name of the coach and the technique or techniques he suggests:

Mike Robertson: eat less
John Romaniello: Full-body strength training
Martin Rooney: Sprints and lifting in circuits
Bret Contreras: Full body strength training plus prowler/Airdyne (metabolic) work
Christian Thibaudeau: eat less, sprints and Olympic lifts in circuits
Chad Waterbury: Full-body lifting plus rope jumping/ burpee ladders (metabolic)
Tim Henriques: Fasted morning steady-state cardio, incline treadmill walking
Mike Boyle: Eat less, Strength Training, Airdyne Intervals; approx. 2:1 work ratio
Alwyn Cosgrove: Basically, it's higher rep, density based, short rest-period resistance training.
Jim Wendler: Prowler / Sled Push 4-7x/week; strength training 4x/week
Nick Tumminello: Strength training, 300 yard shuttle run
Erick Minor: Heavy, full-body workouts done in superset or triset fashion
Scott Abel: "Power Sequences" aka "Combination Lifts"--a form of lifting complexes.

For people keeping score, the winners are: 

Combination of Strength Training w/Limited Rest and High-Intensity Interval Training: 7

Strength Training with Limited Rest Periods: 4

Eat Less: 3

Fasted Steady State Cardio: 1

Note that the people who answered "Eat Less" weren't really answering the question, which was about optimal fat loss workouts.  They admitted that for the most part, asserting the primacy of diet in determining body composition. So the clear winner is strength training (with a preference for limiting the rest periods) plus some form of High-Intensity Interval Training--sprints, sled pushes, work on the Airdyne (surprising to see two mentions of this particular device!).

It's worth noting that Alwyn Cosgrove, perhaps the biggest authority on this topic, does NOT prioritize HIIT in his workouts. I can't speak for him, but at a certain point, a strength-training workout with little-to-no rest becomes a HIIT workout; you're moving from one thing to the next so fast that it's more or less the equivalent of sprinting, only with fewer reps per movement. My understanding is that he's been seeking ways to limit the number of repetitions of a given movement in his fat-loss workouts, presumably for injury-prevention purposes--so HIIT doesn't make the grade, as it's high-rep by nature.

So if you're trying to lose fat and you're not doing strength-training with limited rest and/or HIIT training...the question is...why not??