That's a pretty good workout MegaOctane. You're much like me in diet, 70% healthy and 30% junk (I say as I'm drinking a can of coke now; damn my weakness). I've only recently figured out the perfect workout myself, but I have been finally seeing the results. I've just been naturally scrawny and skinny my whole life, so it's an uphill battle. But even though I'm not as strong as my friends, I'm getting there and definately have them beat on the abbs. I do my workout every second day, as follows.

Start out with gentle warm-up with a yoga stretching routine.

Arm Curls:
Always keep a good heavy weight. 3 sets of 10 reps.

Abbs:
I lie back, put one foot on the opposite knee, the put my arm from the same side as the leg through the hole made by my leg. Then I do crunches that work just my left, then switch and do just my right. It works really well.

Then I do strait-up situps.

Then I do leg-lifts, where I lie on my back and put my legs together and lift them right up, then lower them an inch above the floor and repeat.

All 4 of these are done in 3 sets of 10.

Pushups:
As described above, do them holding the dumbbells. Right now I can only manage 2 sets of 10 because I just switched to this method, but I will work it up to 3 sets.

Thingamajigs:

LOL, can't think of a name for it. I take my arm-curling weight at one side at a time, and lift it at my side up to my armpit. This works those muscles that connect your neck to your shoulder really well.

2 sets of 10, will get it up to 3 when I get used to my pushups. I like to keep all my muscles capable of a consistant number of reps.

As for my legs I'm not sure what I can do. I walk whenver I can, but the sciatica kills me when I walk more than 20 minutes. I tried leg lunges but it made the sciatica much worse.