Which split do you like better for an "on" split and why?

I'm going to couple this with 500mgs Enanthate weekly.

My current routine:

OFF
Chest/Tri's
Back
OFF
Bi's/Abs
Shoulders/Traps
Legs

***OR***

OFF
Chest/Tri's
Back/Bi's
OFF
Legs
Shoulders/Traps
OFF

So two days of recovery on one and three on the other, but longer workouts on the second split. Whatcha think?

The second one or you can try

OFF
Chest/Bis
Legs
Off
SHoulders/Tris
Back/Rear Delts/Traps
Off

Either one of these is good, given that your workouts aren't too long

BIs/Tris/shoulders 5-6 sets
Back 9-10 sets
Legs 10-12 sets
Chest 7-9 sets
Rear delts/traps 3-4 sets

I personally use:
back/abs
shoulders/abs
off
legs/abs
chest
bi's/tri's/abs
off

i hit it with:
chest, calves. abs
bis, tris. abs
off,
shoulders, traps, neck, abs,
back, legs, calves, abs

It is best to allow maximum time for recovery, and to prevent over-training by scheduling out your work outs in accordance to what body parts have been hit a few days prior (i.e, if you hit Triceps on Tuesday, you will want to hold off until Thursday or Friday to hit your delts).

This is why I don't limit myself to a strict weekly split. I train each body part individually and don't limit myself to seven days. I use a 10 day schedule, with a rest day every 2 days. This means maximum recovery, prevention of over-training, and allowance for peak supercompensation.

This also allows me to cycle my routine every week, allowing different muscle groups to fall on different days each week.