Made a team with my absolute favourite type, now I've got all the badges and heading to mount silver.
I did a little breeding, got non-harmful natures, somewhat tried to pilot my EV training but never bothered grinding for EVs so I won't post those.
I'm using no healing items, and playing on "set" as well. Switches are often necessary and that's why after trying a whole bunch of pokes, I ended up with this bulky-oriented team.
Tentacruel @ Black Sludge
Timid Nature (+speed - att)
My firts water-type catch, always been necessary to deal with my rival's Bayleef/Meganium at the early stages of the game. T-spikes help a LOT on teams I can't hit for solid super-effective damage. Clear Body and Poison typing have helped me against a lot of hax. Giga Drain was pretty useful for some of Brock's pokes and Misty's Quagsire.
Lanturn @ Choice Specs
Bold Nature (+def - att)
My answer to other water types, and most electrics. Pretty self-explanatory, good defenses all around, and Electric immunity+STAB is a very important asset to a water team. though once again I need a good filler for my last slot. (also I almost never use Stockpile, which is replaceable as well).
Gyarados @ Leftovers
Adamant Nature (+att - sp att)
Flying STAB is what I needed, it hits pretty damn hard. Also, I found Taunt to be very fun to play with as it stops so much annoying stuff and allows me to get free boosts with gyarados's bulk+leftovers.
Quagsire @ Leftovers
Careful Nature (+sp def - sp att)
I wanted a curse/recover set, then realized you need some crazy Smeargle action to obtain both egg moves, and gave up. Just bred with a slowpoke for Curse. Besides STAB Earthquake, I don't use this poke for much: the problem is, I need that STAB Earthquake a lot, so Quaggy ended up a permanent member of my team anyway. I either curse once of twice if the opposing team is physical, or let it faint after Rain Dance for a clean sweep with my last poke. Both moves are actually replaceable though. Now got Rock Slide for some variety. I found myself not using Curse at all,
Slowking @ Leftovers
Modest Nature (+ sp att - att)
It's a tank or a wall depending on the situation. I chose this over Starmie because the HGSS gamecorner is pure BS (why can't I just buy my coins ;O; ) and it would miss on Psychic, Thunderbolt, Ice Beam, etc. This works anyway, very hard to take down, can either do a ton of damage or stall if toxic spikes are around.
Kingdra @ Mystic Water
Modest Nature (+ sp att, - att)
My last addition to the team, and probably the only way of consistently outspeeding everything on the Champion's team and OHKOing with the appropriate move. Hits just everything hard.
Feraligator -> Once my Gyarados got Ice Fang, it became useless
Lapras -> No useful resistances, not that fast.
Poliwrath -> I needed a fighting type move on my team, but Poliwrath learns only Wake-Up Slap, the inaccurate Dynamicpunch and the (ingame) useless Focus Punch. The only sets I could think of involved Hypnosis and either Focus Punch or Belly Drum+Wake-Up Slap. Unreliable at best.
Starmie -> Pretty darn good on paper except you have to spend your life at the game corner to get a good moveset. Plus, my Quagsire's named HURR and my Slowking is named DURR, and replacing slowking would ruin the picture.
Suicune -> meh, it's a legendary. I wanted to use it in my team, but besides the awsome bulk it doesn't add much in terms of resisances or useful abilities.
Any kind of suggestion for the final battle will be appreciated