Mine is either the Chomper or the Spikerock.

The Chomper can eat just about any zombie whether it's riding a boblsed, a zomboni, or a lawnmower which makes it great at taking out zombies that normally take a lot of punishment.  It can also eat 2 rows out meaning you can put it behind a wall-nut/tall-nut and let it chomp anything that gets near.

Spikerocks are great for survival matches as they're almost unkillable and they deal damage to everything that walks over them.  2-4 Spikerocks is enough to kill just about any normal zombie group and severely damage anything else.

Zombies vs. Plants Gameplay:

Zombies vs. Plants Music Video:

http://www.popcap.com/extras/pvz/

Words of Wisdom, I think some people don't know this great game, might post some pictures and/or videos.

whats this ?

Chompers are great, but I have to go with Repeaters. Not so expensive and deadly. I used them during most of the game

Tried the demo......Awesome!

I like the tall nut. There's an amusingly homo-erotic article about them on RPS-

http://www.rockpapershotgun.com/2009/05/05/tall-nut-here-comes-my-man/

Chompers are useless for me. Yes they have that 2 space range but once they eat a zombie it takes forever before they are finished chewing.

Other than Sunflowers (duh) I would say my next favorite is the repeater although they become a bit expensive later on.

I just finished the Adventure Mode lastnight and I have 18/20 Puzzle Levels completed and 13/20 Minigames. After that it is on to Survival Mode.

Chompers are great to get you out of a hurry (like a Zomboni, or to put them in the last tile when the zombie is about to reach the house). And putting two Chompers in sucession, or a chomper behind a Tall-nut are deadly combos. Or you can always put the chomper, let it eat the zombie, remove it and put another one

I would rather spend that 150 on a cherry bomb and take out 4- 5+ zombies at once than spend 125 per Chomper to take out 1-3.

let us say a large wave of zombies come and you are setting up your defense and the front line is 6 Tall-nuts and 6 Chompers. Even though those Chompers can eat a zombie, it takes way too long before it is done. That combo tends to become useless later on. 

Sunflower+Peashooter+Cabbage-pult+Cherry Bomb+Wallnut was all I needed to complete this game.

But a Cherry Bomb takes a hell of a time to reload, a chomper not so much