Okay, there may be a few holes.
Tyranitar and Dragonite will tsay for sure, and I may sub out Metagross for someone else. But most of my pkmn would have earthquake, which takes out electivire
Yeah, and there goes your buffeter for Earthquake. :\ And Electivire was merely an example. There are many other Physical Sweeper Pokemon out there that can learn moves like Ice Punch and Earthquake. Take Medicham for example.
Dragonite is a flying type that can easily take out Medicham. And pkmn like that don't get STAB, which reduces the effectiveness of them.
And you said where's the fun in that a few posts ago... this team will be at the end of the game. I don't know what my team will be for the main storyline e.g. 8 gyms + elite four, but it may look like this:
Empoleon
Staraptor
Luxray
Leafeon(can you get this pre elite four?)
Rapidash
HM slave
I've got:water, steel, normal, flying, lightning, grass, and fire. plus and HM slave to put in to use a quick revive/potion of some sort. I normally don't need too many pkmn while I go through the journey. In fact, I played my bro's fire red version using only Blastoise and an HM slave. By the time I got to the elite four Blastoise was in the high 70s.
Edit: I HATE the whole Chansey trio. They are only usefull as blockers and with a well trained fighting/steel type(my fav Lucario) they are easily beat with a physical attack move such as close combat.
@CL: pkmn is confusing if you let it be. You can get through the entire game without knowing anything about stats, as the pkmn you come across early on all have decent stats. If you are really into the game then it gets confuzzeling with all the natures and such. Speaking of which, do you breed for a certain nature etc.?