So you want an infant seat then to start with, or were you planning on starting with a convertible? If you're looking for an infant seat, I'd look at the Graco Snugride 30/35, Chicco Keyfit, and Safety 1st onBoard 35.
If you want to start with a convertible I'd look at the Combi Coccoro, any of the Britaxes with infant wedge (bought separately), First Years True Fit, Graco My Ride, Evenflo Triumph 65.
If you're thinking infant seat now, then a convertible later, then I wouldn't worry about the convertible now. In the year plus between now, when the baby is born, and when they outgrow the infant seat there will be new seats on the market that may be The Best Seat For Your Child And Car. And even if the perfect seat is something that's available now, if you get it and store it, then it may expire before you're done using it. Whereas if you wait to buy you'll get more lifespan of the seat to use.
Wendy