As several people have pointed out, there is no ideal party for every situation, but assuming a fairly combat-focused type of game, I'd probably go with the following.
1) Dwarf Bbn/Ftr (Front-line tank. Bbn is really nice for rage, uncanny dodge, and fast movement once he can get some dwarven plate.)
2) Dwarf Ftr/Clr (Ftr to 4, then cleric all the way. Secondary front-line with extra healing and low-level buffs.)
3) Gnome or halfling Wiz (Artillery and utility spells.)
4) Human Clr (Indispensable for healing, turning, and spellcasting-take a high cha for turning and diplomacy)
5) Halfling Mnk/Rog/Drd (Find one of those feats that gives an extra favored class, start with rogue (or infiltrator) for skills, next few levels as monk for Wis bonus to AC and fast movement, then alternate Rogue and druid. Focus on the critical rogue skills- hide, move silent, search, open lock, and disable device, and use spells and wildshape to support the scouting role. When you can, take Tracking.)
6) Gnome gadgeteer (good mix of firepower, mechanical servants, and other abilities, and take the burden off the rogue for locks and traps. If you're limited to core classes, I'd say Elf Sorceror with a mix of artillery, buffs, and summoning.
1) Dwarf Bbn/Ftr (Front-line tank. Bbn is really nice for rage, uncanny dodge, and fast movement once he can get some dwarven plate.)
2) Dwarf Ftr/Clr (Ftr to 4, then cleric all the way. Secondary front-line with extra healing and low-level buffs.)
3) Gnome or halfling Wiz (Artillery and utility spells.)
4) Human Clr (Indispensable for healing, turning, and spellcasting-take a high cha for turning and diplomacy)
5) Halfling Mnk/Rog/Drd (Find one of those feats that gives an extra favored class, start with rogue (or infiltrator) for skills, next few levels as monk for Wis bonus to AC and fast movement, then alternate Rogue and druid. Focus on the critical rogue skills- hide, move silent, search, open lock, and disable device, and use spells and wildshape to support the scouting role. When you can, take Tracking.)
6) Gnome gadgeteer (good mix of firepower, mechanical servants, and other abilities, and take the burden off the rogue for locks and traps. If you're limited to core classes, I'd say Elf Sorceror with a mix of artillery, buffs, and summoning.