These are among my favorite suits. Not in any particular order, love each suit for it's own unique qualities.
Godzilla Final Wars
Regardless of whether people love or hate this movie, I think this one of the best suits. Not only does he look sinister and badass, but I love how streamlined he is. Kinda like a Godzilla version of Bruce Lee.
Godzilla 2000 / Vs Megaguiras
Can't say enough good things about this suit. Was a departure from the classic suits, with green crocodile like skin, and purple crystal-like spikes.
Destroy All Monsters / Godzilla's Revenge / Vs Smog Monster / Vs Gigan
My favorite showa suit. Just love it!
Godzilla Vs Biollante / Vs King Ghidorah
Love the majestic qualities of this suit, very bulky and powerful! A true King of the Monsters.
Godzilla 1985
He looks like a freakin' vampire! Awesome!
Godzilla Vs Megalon / Vs Mechagodzilla / Terror of MG.
This guy is just so darn cute! What's there not to love