What car seat do you have for your LO?
At the moment, I'm using the car seat that came with my pram but Holly-Kate is quickly growing out of this because she is so long. She looks so squished up in it too. Its also a real struggle carrying the seat to and from the car to the house as it is so heavy and then when Holly-Kate is in it, it's even heavier and it's killing my back.
I'm looking at getting a seat that stays in the car so I can just put her in and take her out without having to remove the actual seat. I've been looking at the ones that can be used from birth up until approx 4 years. I haven't got a clue what important features I should be looking at and what ones are popular, reliable and safe.

Does anyone have any advise or suggestions on car seats?

Yes.

Get a Concord Ultimax.

Problem solved! They are excellent.

My son, age 4 has a  graco nautilus 3 in 1 car seat.  He loves it.  

The thing about this seat is that since it is 3 in 1, it will last a long time.  I don't know if you can use it from birth but you should be able to use it from age 2 and up.  

You could also get a Concord Ultimax as Maenad said.  My friend has one for his kid and he says it's great.  

If you have the money you could also get one of those neat car seats that turn 90 degrees so you don't have to turn your body everytime you need to strap your baby in.