I'd have to go with the chain rod as well. The ability to pull enemies into spike beds in the ancient ruin stages was a hell of a lot fun.
Although I wish you could pull lighter enemies over your head and fling them behind you, into a wall, off a cliff, or what ever your fancy for unique murder would be. Oh, and swinging on walls and ceilings Indiana Jones style is very fun! Although I wish he could do more intricate things with it. I know that's asking a bit much for a gba game, but damned if it wouldn't make it more fun. That's what I find to be very much like what zero's good at. It's never been about getting bigger and better stuff to unload on to enemies for him. He just finding cooler ways to use what he's got. Which is why I like him so much in this series. He's very resourceful and efficient this time around. Maybe they'll bring this weapon back sometime?
The Recoil Rod takes close Second. Not only is it strong enough to break through shields but it has enough force left over to send anything else behind it flying right off the screen and into whatever's unfortunate enough to be in it's path(And it works great on bosses too, but that's about the only step up from the chain rod). It can also do the same for you only to your advantage, whether pushing heavy blocks around or catapulting you up to an unreachable platform. So if your looking for raw power to be your war buddy than this is a great weapon to use!
Third would have to be the Tripe Rod. I don't care what you guys say, It can do great damage if you know how to use it. It has the piercing power of the recoil rod and can be used to po-go stick your way across a sea of enemies. I especially had a lot of fun getting revenge on fefnir when ever he threw me up into the air only to have me come down on top of him and plunge into him with my extension rod!(and don't get me started on how it works on levi) Also the charged attack deals just as much damage, if not more with the inclusion of elemental effects, as the triple attack. But because that was thrown into the chain rod this little gem of a weapon gets bumped down sadly... :(
Coming into fourth is the shield boomerang. I don't know why you guys neglected to include this one in your line up, maybe your all just lazy, or didn't care enough about it to even bother to give a damn, but that's fair enough since I don't like it that much either. This weapon would be good because it mows down enemies like grass and you can do a lot of cool stuff with it in the 3rd installment. But playing jump rope with this thing is about the most amusing thing you can do with this. I may be wrong but other than being a spinning blade of robo-bloodshed and death this thing actually makes a pretty poor shield! Since the enemies bullets come in so slow you would be better off dodging them the old fashioned way then using your so called shield to deflect them back at them. It just takes to long! The bullet erase feature for your Z-saber comes in more handy than this. The least it could do is redirect the shots into enemies you hate slightly more that the ones shooting because they're a little more difficult to reach. I really wish it could do more with it like bounce it off of walls, or maybe let you catch it when it returns and fling it back into enemies fire again only with more momentum. So you could keep bouncing it off a wall, back and forth killing anything in between. Oh, and it should always be able to deflect fire, even while in boomerang mode! The only thing that keep this thing above last place is it's fast paced, killing spree, usefulness that is the boomerang!
Fifth, oh yes! I get to rant soem moar!, is the Zero Knuckle. Why is this fifth you ask? While admittedly, stealing other enemies weapons was very cool at first, I soon realized that there just weren't that many weapons out there that I particularly favor. What with being poor rehashes of all the other really good weapons in the previous titles. While the only redeemable quality this gimmick has is the ability to grab on to ropes and poles, You have to wonder "Did I really need an whole new weapon just to be able to do this? I wouldn't be so hard on this one if I could use it against bosses in the same manner. Think about it, grabbing one of Sol Ti-whatever smokin' hot bot's name is spinning blades and tossing it right back at her stupid sadistic face would have been the one think that would have kept me from putting the game down when I finished it. I Also would have liked to use it to grab entire enemies and chuck them at all his little friends like I could with the recoil rod or like I could with one of there weapons, or maybe use him as a humanmaverick shield to keep my hair dry of bullet fire while using his gun to fire back! Over all it's not a bad weapon, it's just one I could find a lot of uses for.