Please do not worry about setting a bad habit. Your baby is so young. He is going to change his sleeping habits often in the next 6 months. Do what works! Co-sleeping is a great habit. Babies thrive when they are physically held and loved. This is a good thing! There are things you can do to make co-sleeping safe:
http://www.askdrsears.com/topics/health-concerns/sleep-pr...
Both of my boys co-slept with us during different phases. My oldest was not a good sleeper at all until I let him sleep with us. This was the only way for us to get any sleep at all. He use to wake up every time I tried to put him back in his crib.
One trip I learned for nap-time was to lie down with him in the middle of our bed, nurse him to sleep and the slowly role away. This was before he could role over.
Once he learned to role over, my husband decided it would be safest to remove our bed frame, place our mattress and box springs on the floor and surround the bed with pillows, just in case he fell out. He never did fall out, but my husband slept better than way.
ETA - Both of our boys began sleeping in their own beds when they were 16 months old. They did, from time to time, visit our bed in the middle of the night, but we have had no trouble whatsoever getting them to sleep in their own bed.
There is a huge difference between allowing a newborn to sleep in your bed and allowing a 2 year old (or 8 year old) to sleep in your bed. A newborn has very different needs than a 2 year old. You have plenty of time between now and 6 months from now to change things if it is not working. Right now co-sleeping is working, so why change what ain't broke? When it is not longer working (for one of you), you will find a way to change something so that you are once again both sleeping at night.