I remember the first time I saw a FEAR-ttata, and yeah I was like, well shit. Then I had a vaporeon with leftovers for it to fight and just stomped the little fuck into the ground and proceeded to destroy the person I battled cause that was like their big plan for some reason.
As for my best pokemon ever, well, that's a three way tie.
<spoiler=Vaporeon>
http://fc03.deviantart.net/fs50/i/2009/295/a/7/Realstic_Vaporeon_by_Leashe.jpg
Vaporeon pulled major work in G/S/C for me, tanking three T-bolts (two crits) from a mewtwo and beating its ass into submission after. Since then its been a stalwart on my team and usually my water backbone. It's hard for me to pick any water type if I have the optino for vaporeon.
<spoiler=Empoleon>
http://i427.photobucket.com/albums/pp360/ZebraRandig/Realistic%20Pokemon/Empoleon.jpg
Unless of course its empoleon! Empoleon was beast to me, even after everyone was like "oh, piplup's got a dumb design" "oh, piplup's so dumb, you can get a turtle with a tree or a fighting monkey instead" "oh piplup doesnt learn any moves." all fair points, however, that dual steel, DAT DUAL STEEL made him beast, and i hold him as the best water starter in the game, yes even over swampert (though both are basically the same resist and weakness wise in terms of numbers). Besides, Empoleon can't be toxic'd. huge advantage.
<spoiler=Venusaur>
http://www.animalhi.com/thumbnails/detail/20121109/nintendo%20pokemon%20video%20games%20bulbasaur%20venusaur%20ivysaur%20insects%20digital%20art%20artwork%20white%20background_www.animalhi.com_72.jpg
My third would probably be bulbsaur especially in sixth gen. He's just so versitile, either an attacker, supporter, minor tanker. Gets that grass/poison with enough powders to cripple. Plus with how early you get venoshock, I mean raelly? I had bulb then, with Poi. Powder, and found that TM and just cruised straight through anyone who didnt resist/immune poison. and when I got sludge bomb to tandem, oh man.