Loosing 40 lbs in 6 months

[Woodson]

Okay, so I figured I would set myself a goal. I need to loose 40 pounds, yes I am overweight and I'm doing this to get healthy and not to be in high risks of heart failure, heart disease etc. I got my diet straight and I know what I'll be doing with that. My problem is trying to get a routine going, I know cardio is the most important at this state which I don't have a problem with, I like doing cardio but I also want to include weightlifting days. Here are some routines I have in mind, If you have any suggestions or which routine you think would work the best I appreciate your help.

Routine 1 :

Mondays
-Cardio (45-60 mins on a treadmill)

Tuesdays- Chest & Back
-Bench press
-Incline Dumbbell
-Flies
-Lat machine pulldowns
-Seated cable rows or T-bar rows

Wednesdays
-Cardio (45-60 mins on a treadmill)

Thursdays- Arms
-Barbell curls
-One arm dumbbell curls
-Reverse curls
-Lying extensions
-Cable pressdown
-One arm triceps extensions

Fridays
-Cardio (45-60 mins on a treadmill)

*For lifting days - doing 5 sets
1st set- 15 reps or slightly more
2nd set- 12-10 reps
3rd set- 10-8 reps
4th set- 6 reps
5th optional set- using same weight as in 4th set try to get another 6 reps.

ROUTINE 2:

Mondays
-Cardio (45-60 mins on a treadmill)

Tuesdays- body workout
-Bench press
-Incline Dumbbell
-Lat machine pulldowns
-Seated cable rows or T-bar rows
-Barbell curls
-One arm dumbbell curls
-Lying extensions
-Cable pressdown

Wednesdays
-Cardio (45-60 mins on a treadmill)

Thursdays- body workout
-Bench press
-Incline Dumbbell
-Lat machine pulldowns
-Seated cable rows or T-bar rows
-Barbell curls
-One arm dumbbell curls
-Lying extensions
-Cable pressdown

Fridays
-Cardio (45-60 mins on a treadmill)

*For lifting days same sets as in routine 1

ROUTINE 3:

Switching days during the week

Week1: Mon, Wed, Frid - Workout days, Tue & Thurs - Cardio days

Week 2: Mon, Wed, Frid - Cardio days, Tue & Thurs - Workout days

Week 3: Mon, Wed, Frid - Workout days, Tue & Thurs - Cardio days

Week 4: Mon, Wed, Frid - Cardio days, Tue & Thurs - Workout days

And keep switching them like that week after week, althought I'm not sure about this one cause there might be too much rest for some muscle groups.

What do you think?