Buy the infant seat you like best, but arm yourself with info first so that you are not surprised. First off - consumer reports is NOT what you want to go off of when it comes to car seats. Car seat experts (CPSTs - child passenger safety technicians) agree the system they use to test seats is suspicious, especially since they refuse to release their methods, or even let CPSTs be involeved to make sure they are using the seats correctly.
Secondly - if you are truly wanting your child to get near 30lbs in a carrier, or use it to at least 12 months or beyond, the Graco SafeSeat1 is your only choice. The Keyfit30 is exactly the same seat as the Keyfit22! Just tested to a higher limit. So your child would have to be quite chunky to still fit at 30lbs, and then would be uncomfortable b/c the seat isn't any wider than the Keyfit22, either. Safeseat1, however, is both taller and wider than the Graco Snugride. Plus, the built-in lockoffs on the safeseat1 are awesome!
Using a carrier for longer sounds like a good thing, but remember a few issues, first. Only newborns need to be reclined to 45 degrees (to make sure they don't suffocate by their heads rolling forward). Once an infant has good head control, they can go to 30-45degrees, in other words, sitting a little more upright. Some infants will actually complain if they are too reclined when they are 7 months+, and in a carrier there is next to nothing you can do about it but buy a convertible car seat so he can be more upright, and then you wasted extra money on a 30lbs carrier.
So, on to the topic of convertible car seats. They are in no way less safe than infant carriers. Carriers were invented for convenience, and are in fact not the brightest thins we ever came up with. We are now seeing more and more cases of delayed developmental milestones b/c babies spend SOOOOO much time in carriers, bouncers, swings, and other devices that keep them in that same position not using their muscles much. You see babies in those seats in stores, at church, at playgrounds, restaraunts, etc. despite the fact that manuals specifically say for use in the car and stroller only. So when you look at it that way, they don't seem quite as convenient anymore, do they? They can also be increasingly awkward to carry as baby gets bigger. A sling, pouch, or wrap is a much better idea for shuttling baby around the store in. Babies love it and it keeps your hands free. You can even breastfeed in many of them!
Back to convertible car seats - they are equally safe as infant carriers, and in fact, some people skip the carrier stage altogether, and there's nothing wrong with that as long as you make sure you purchase a convertible that will fit a newborn.
A few good ones:
The Evenflo Triumph Advance (not the original Triumph, make sure it says Advance) is a great seat. $150 version at Babies R Us has padding similar to Britax seats, top slots of 17", harnesses to 35lbs rear facing, and 50lbs forward facing. $120 Walmart version just has little less plush padding. Wide open belt path, easy to install, though it doesn't have built in lockoffs. The harness adjusts at the front of the car seat, you don't have to take the car seat out of the car just to raise/lower the straps. It's one of only 2 seats that does this (The Britax Boulevard is the other, I believE), and it has infinite harness adjustment so the harness always fits perfectly until its outgrown. No more tugging straps to tighten them either. You tighten and loosen the harness using knobs on the side of the seat. As a major bonus, it can be used in a recline position even in forward facing mode. Awesome for kids who still sleep in the car. I LOVE THIS SEAT! LOL My son, who is too big for every other car seat at Walmart has the same amount of room in this as the Britax Marathon.
Cosco Scenera is a steal and fit newborns well, too. Its possible a Britax Decathalon or Boulevard would fit your baby, but that depends upon how tall your baby is at birth, since its bottom slots are slightly higher.
Planning to have more kids definitely means you want quality, however, keep in mind that car seats expire 6 years after the date of manufacture, regardless of use/storage, so you may end up buying another anyways.