I hate the Dawn remake. The zombie baby bullshit is straight up comedy and something I always imagined would be a thing with zombie law, but to see how it was done... the beginning was good and there was a video diary extra on the dvd about the guy from across the street from the mall and how he was surviving that was okay (reminded me of the Day by Day Armageddon books). Other than that it was straight trash.
To answer the op though I would have to echo most of the recommendations in the thread.
The original Romero trilogy, obviously. Still not been beat, not even close.
Dead Set - Excellent, only let down by its budget and shaky cam effect Brooker chose to use. It has a great sense of dread though, which is what I look for in a zombie film.
Train to Busan - Was a nice surprise, didn't expect it to be as good as it was.
Zombi (or Zombie Flesheaters as it was known here) and Zombi 2 - 2 is better, but I have a special place in my heart for Zombi, love the soundtracks and practical effects.
The Dead - Watched this around the same time the DayZ mod first came out, it was a perfect fit.
You already mentioned the 28 Later films.
Edit: Seems I was getting mixed up with Zombi 2 and 3. Not used to the numbering on them in the UK.