I like to balance my team with different types.
LG - Venusaur, Pidgeot, Lapras, Ninetails, Raichu, Hitmonchan
Ruby - Blaziken, Wailord, Crobat, Walrein, Groudon (I made this team when I was 10 so I can't remember who the 6th one was)
Diamond - Empoleon, Staraptor, Azelf, Roserade, Dialga, Luxray
Platinum - Empoleon, Luxray, Gallade, Staraptor, Flareon, Roserade
HG 1 - Typholosion, Pidgeot, Starmie, Glaceon, Ampharos, Victreebel (my first play through now on Platinum)
HG 2 - Feraligator, Togekiss, Arcanine, Umbreon, Riachu, Sunflora
HG 3 - Megainum, Crobat, Magmotar, Espeon, Electivire, Kingdra (My current team)
White - Serperior, Swanna, Victini, Musharna, Zebstrika, Simipour
Black - Samurott, Swoobat, Simisear, Beartic, Emolga, Lilligant