A couple comments, since no one seems to have mentioned them:
Just a question about this. No matter how I time the dair I have found that it is impossible to avoid the last hit unless the attack finishes in the air. The last hit is "push effect" due to Kirby's landing on the ground, and is what prevents Kirby's dair from being a combo monster. However, I've had some occurances when I would perform the dair and even though the last hit occurred due to FF'ing the opponent wasn't pushed away.
I've found if you move away from your opponent as soon as the first kick hits, if you go just far enough, the last hit won't hit (It will go off, but they are out of its knockback range), yet are still in grab range, so I tend to do that. Granted, there are no good human players in Dayton, so I'm mainly doing this against comps, but it seems to work pretty consistently.
Also, as someone previously mentioned, people expect the Gonzo combo now if you Fthrow them at low %s. For this reason, I tend to do Fthrow-->Uair (which makes them expect a Gonzo)--->Dthrow--->Utilt (which makes them expect another Utilt or Usmash)---> SHDair (avoiding the last hit as mentioned above. This (using a Dair at this point) works better against big chars, as they usually can't avoid this. Medium sized chars have a little time to react, and I haven't really managed to get it to work on lighter chars much.)---> any other throw, Fthrow to hammer if your opponent is ********, a computer, or confused (again, this is untested against human players). I tend to use this after having done the Gonzo the previous stock, so they expect that (well, technically comps don't expect anything, but I try to play as though they would...). Of course, this full sequence only works at very low percentages and does quite a bit of damage. I've gotten comps from 0-60 or 70 something percent (depending on how much of your Dair hits and if you can follow it with a hammer at the end or not) with this, so I really hope it works on humans.
Also, Ftilt can be effectively followed into a Fsmash at lower %s. That's mainly what I use it for.
Also, while there is definitely lag on this as Kirby stops, I've found running at them then doing a dtilt is pretty effective. Most people expect an attack and shield, or they try to hit you first, but usually Kirby manages to get flat on the ground before they get it out, allowing it to sail harmlessly overhead (You know what I'm going to say, right? I haven't tested this on human players either.)
Also, (yes, I have a lot of "also's") I'm sure everyone knows this, but since no one posted it I will, stone form is pretty good for hitting people in water, as they can't dodge and it reverts you with only the lag you would have when you normally jump in the water (too risky against spiking chars though, IMO).
And finally, I love using cutter for mindgames. Doing empty cutters on a ledge may force your enemy to try something which could be characterized as stupid. Also, they will start to expect you to grab the edge when you do it at a ledge, and not expect the shockwave when you finally decide to land.
Sorry, that's a bit long and potentially useless, but thought I should share anyway.