Being a fan of the big guy, gotta say I like Godzilla 2000 probably the best. The scene at the end with the guy and the cigarette just brings home the inevitability of defeat at Godzilla's hands...
Probably my favorite piece of Godzilla/Giant Monster hardware are the Maser Cannon trucks. They rarely do much to the big guy, but they look hella cool doing it!
http://godzilla.wikia.com/wiki/Maser_Cannon
Still waiting for the next sequel to Gamera (post Gamera III), but it's been well over a decade now so I don't think we'll get to see the other big guy taking on the hordes of Gyaos monsters that we were teased with at the end of G3... If you enjoy these movies. the Gamera Trilogy they did in the '90s is worth the effort!
Looking forward to see how the big guy fares this time around. No Matthew Broderick, and JJ Abrams isn't involved, so that's a good sign...