How many days rest between weights sessions?

I have a very basic split routine, designed to build my chest, shoulders, and back. One day I do:
Bench press and Shoulder press (I know only two, but they're compound exercises, and I really hit them hard).
The other day I do:
Chin Ups and Bent-over rows.

I have a three day cycle, first routine 1, next day routine 2, then a rest day. I'm thinking it might be better to have a rest day between routines 1 and 2 as well, giving three days instead of two before hitting the same muscle groups again.

What do people think?

Doing a very limited number of exercises and hitting them hard has proved more successful for me in building muscle than trying to do say 8 different exercises in a routine (and it saves time!). Is this a recognized method?
Answer:
You should have a day of rest or cardio inbetween lifting days. Train your whole body once every 6 to 7 days. I personally wouldn't train chest and shoulders on the same day as you are working two large muscle groups at the same time. Try to work one large muscle group and one small muscle group in the same day, ie. chest and triceps on Monday. Then rest a day or do cardio only on Tuesday. Perhaps work your back and biceps on Wednesday. Cardio on Thursday. Shoulders and legs on Friday. Cardio Saturday. Back to chest and triceps on Sunday, or just rest Sunday. Get your abs in at some point, perhaps on cardio days. Don't forget proper diet. Also switch things up every now and then to break monotony and keep workouts fresh.

These are just my personal suggestions and the way I train based on what I've learned through research. I am not a qualified trainer. You may want to pay for a few sessions with one.

---