We tried a few different combos earlier on, but now what works for us is this:
We have our mattress on the floor with our son's cot mattress on the floor next to us. He has day naps on our mattress. He starts night sleeps on his mattress, then when he wakes he comes up onto our mattress.

Re the Sids recommendation> I've done some research and tha actual statistics on baby deaths reveal that co-sleeping is MUCH safer - so I get really angry that sids and kids recommends a cot. They don't actually have any good reason or evidence to show WHY they recommend this. The trouble with stats is that they record co-sleeping in a variety of situations, eg on a couch/beanbag etc, which just isn;t safe. When SAFELY co-sleeping, there are only a handful of SIDS cases at most; and 'accidents' are just as rare.

Basically you make sure that the mattress is firm, baby can't be suffocated by bedding/pillows, or get trapped anywhere. Also you shouldn't co-sleep if your or your partner smoke, are drunk or affected by drugs......

We co-sleep because we like the bonding, it feels natural, we don;t have to get up in the night, and we believe its quite safe to do so.