I was in the exact situation when pregnant with my now 5-month-old.
I have 2 very affectionate Siamese, one who has a history of sleeping on my face. So I was also worried, as I wanted to co sleep but didn't want the cats to unknowingly endanger baby. I had heard of many stories where pets kept their distance, but I needed to see how my animals would react to my baby.
Shutting the cats out of the bedroom was considered, but these are Siamese. They are loud, and they don't take no for an answer. So that was going to be a tough thing to do, and yowling cats didn't seem conducive to helping baby or frazzled parents sleep.
I bought the Arms Reach Co Sleeper and bought the canopy thingy that goes over it. I wanted to know that I had one option that would keep the cats totally away from the baby if need be. For the cosleeper to be totally cat proof, it meant having the detachable rail up between the cosleeper and our bed - meaning that I'd need to get up and move the canopy to get to the baby at night, not ideal in cosleeping terms. But still, if it was a safety issue, I wanted to have that option.
We've only used the co sleeper the very first night that baby came home. Like many of the other respondents' pets, my cats kept their distance and have taken to sleeping at our feet. Still, I don't regret getting the cosleeper because I didn't know what to expect. I may end up using it again once he starts crawling and I want somewhere secure to put him between the time he goes to bed and the time I go to bed. And I'll probably sell it on Craigslist afterward.