you basically have 2 options:
An infant carrier style - which as you have said will need replacing once baby is around 1 year old only ever goes rearward facing.
Pro's of this are that when baby is younger, they are fab for transporting baby round for short trips, eg. nipping into the docs/supermarket/mates house and saves waking baby up if they fall asleep in the car, you can carry them into the house without disturbing him/her.
Many are also compatible with various prams.
Have you chosen a pram yet? The Cabriofix is compatible with quite a few different models
This means you can attach the cabriofix to the pram easily, again to save disturbing baby (although baby should only be in car seat for 2 hours at a time before a break)
option 2 is to buy a combination seat which is much bigger and stays fitted in the car all the time, ie you would have to take baby out every time.
However, these last from approx birth - 4 years and cost about the same as a second stage seat that you would have to fork out for after the Cabriofix. so much better value for money in the long run.
It all depends on your lifestyle - do you imagine you will be walking most places with the pram and not using the car (and therefore car seat) much?
in which case you could probably manage with a combination seat staying in the car all the time.
or will you be nipping out for short trips to the supermarket/shopping centre/doctors etc that will involve taking baby in and out of car regularly? if so, an infant carrier is probably more practical.
You can get pretty cheap infant carriers if you are not bothered about it being compatible with your pram.
if you do decide to go for an infant carrier and you have a 3 door car, it will make your life alot easier to get a base as well! But bear in mind that although there are lots of infant carriers available out there, not all of them have compatible bases.
I would vote for the Maxi Cosi Cabriofix too.
In my experience, the easiest and simplest to use, base compatible and lots of prams compatible as I mentioned.
I think just about everyone I know has a cabriofix and I dont know anyone who has regretted their purchase - they are just so user friendly!
HTH xx