Welcome Allison!
(And again, I'm SO sorry for questioning you on your stroller bargain post...you were so nice about it!)
Anyway, I'm one who did the convertible seat from birth. Well, we actually had a Snugride for like the first 2 weeks, but then we went straight to our Britax Boulevard and couldn't be happier.
One "con" you'll hear people mention about using the convertible instead of the infant seat is that you'll have to wake up a sleeping baby when you take them out of the convertible to go inside. This was never a problem for us, because DS rarely sleeps in the carseat, and when he does he's usually sleeping deeply enough that he doesn't wake up.
I haven't missed the infant seat, but I will tell you this - if you go straight to the convertible you absolutely MUST have some sort of baby carrier (I recommend a pouch). Otherwise, grocery shopping and things like that will be nearly impossible.
Good to have you here - you're gonna love it!
Stacy
Wife to K
Mommy to A (5) and twins E & S (1.5)
The biggest mistake I made is the one that most of us make...I did not live in the moment enough. I wish I had not been in such a hurry to get on to the next thing: dinner, bath, book bed. I wish I had treasured the doing a little more and the getting it done a little less. - Anna Quindlen