Good on you man. Getting back to the gym is sometimes hard to do, but while most people here will say cutting back on food is key, I tend to disagree. Though I will agree eating healthy is key, and reducing the amount of processed foods you intake (definitely cut out soda), I think the best results for losing the pounds and body-shaping is: consistency in a routine like you've said. Obviously don't over do it on the calories count. But cutting back on the calories isn't always the best answer especially if you're consistently being active. You need those calories for your body to replenish the damage you're putting it through by working out, as well, with doing lots of routine activity and eating enough to counter it, you'll balance your metabolism which is something that'll help keep your body from storing fat.
RE your regimen:
First, I think a 3 day rest is too much. But if you are set on it, I'd would say at least add a 5th day of just doing straight cardio, no weights. Something like the row machine that has a high intensity effort, but without having to spend as much time as running or going on the bike machine.
I'd also recommend doubling up on the isolation days, targeting the major muscle groups -- 2 days of Chest, 2 of Back, then put Legs and Shoulders together in one day. That way you are giving your muscles only a day to recoup before you tear them up again. If you wait too long between workouts, your rate of results will be slow and it'll take you longer to increase weights 'cause your body gets too complacent and you want to be keeping a consistent muscle-breakdown.
For Chest days, I like to pair biceps with chest exercises because most chest exercises will work the tri's anyway and I don't want my chest exercises to suffer due to tired triceps. Same with Back days, I pair triceps with them so to offset the workouts.
3 - 4 Chest workouts are good. With the flys I'd recommend doing Fly Bench Presses with Twisting your wrists inwards on extension. Like this:
You don't need to use heavy dumbells for this exercise, 'cause it puts a little strain on your wrists, start off light. This exercise will target the inner pectorals, something that a lot of guys neglect. Bench exercises work your outer pecs more, the area closer to your armpits, while this twisting action will force your chest to "squeeze" as you turn the dumbells inward.
Back: Dead lifts are fine and dandy, but I would recommend using the cable machine for a couple Rotator Cuff exercises (there are dumbell variations on these as well). The Rotator is another muscle that gets very little love, and is one of the most important small muscles your body uses for stabilizing when you're lifting things. Having strong Rotator Cuffs will help prevent injuries when exercising anything upper-body, as well it helps add good definition to your scapula area.
These two are great:
Legs: Squats, quad press, and calf presses are good. But do not neglect your hamstrings. You need to balance your quad and hamstring exercises to prevent injury. These two muscles are the biggest on your legs and the work together, like tri's and biceps. If using the hammy curl machine is too difficult at the beginning, I recommend adding Lunges to your leg workouts. Carry a couple dumbells and lunge forward, down to almost touching your knee to the ground (but not touching) then stand back up.
These are awesome for working multiple muscles in your legs, including quads, hammies, groin and calves.
For Shoulders there are 3 exercises I recommend for getting those Dwayne Howard shoulders:
Arnold's (made famous by the Governator himself)
Works the middle and posterior deltoid (shoulder) muscles.
Incline-bench reverse flys
Great for anterior shoulder muscles
Incline Front raises
This picture shows her going passed proper form though, don't go further than parallel-to-the-ground to avoid injury. These are excellent for working out the interior deltoid (yet another small muscle that gets neglected), and helps round out your shoulders more in conjunction with the other shoulder exercises.
Start off with lower weight if you're unable to get through a set. These shoulder ones can be pretty difficult to get started on, especially the Incline Front Raises.
One more thing I like to do is right before my cooldown and stretching in every workout, I sneak in some sit-ups, just so the stomach muscles doesn't get left behind.
I really hope this gives you some ideas for your workouts, and mad respect for wanting to transform yourself: it's all about staying consistent. My workouts usually last me about 1 hour if I'm not dilly-dallying and straight business-like in the gym. Add maybe 15 extra mins for cooldown/stretching. For reference I'm a 6 foot, lean 165 pounder.
