Some people like to start the game with one or two characters just to get the feel of the game and to make their heros stronger. In fact, some people have played thru with only one character. I currently have a party of 4 and it's worked very nicely. As for your desire to use all 6 races; it's not really necessary. Dwarves and Elves are the only real races that are distinguished. Though gnomes get made fun of in the first town, and a halfling can be cool towards the end of the game when you start sneeking around Lower Dorn.
For the gnome, i'd say the only worthwhile class is the Cleric/Illusionist. it's the only multi-classed specialist mage possible; so that means lots of spells.
I'd also advise a Half-elf Cleric/Ranger; he's the tank. In fact, i played my first "one character game" with this class (second time around, i used a cleric/mage; no problem)
As for the Halfling; make it a fighter Thief so he can actually fight?
umm, dwarven fighter clerics can be powerful as well.
paladins are cool, but they are too gooddie-goodie for me (in some cases, their only option is to kill the evil guy). Rangers are way cool cuz they get an extra attack when not holding a shield.
Bards are actually pretty cool if you have Heart Of Winter installed. For the first time ever, a Bard actually learns new songs as he goes up levels; about 6 in all. songs for immunity to fear, thieving skills bonus, hold person, and the final song regenerates hitpoints and lowers ac by 2 for everyone. Bards also get some extra dialoge options in the game. Mainly in Easthaven, but even later you'll see that a bard is master of the artsy and drunk when talking to characters. their spells don;t progrss so fast, but can be very powerfull at summon spells and things like flame arrow.
Druids are very cool un Heart of Winter as well (though i've yet to play one). they get a whole bunch of shape change abilities, immunity to poisons and fatigue and some special spells.
i've never played a 6 player party. frankly, i can't understand why someone would want to. it's just too many characters to have to move around and keep from dying. the most i'd ever play with is 5. Multi-classing is so cool, but with 6 people in the party, you're almost better off choosing single classes or dual classing a human.
My current party is of 4.
Half-elf Cleric/Ranger
Gnomish Cleric/illusionist
Half-elf Bard
Human thief/fighter
The ranger has never let me down, he's been the tank. The gnome is a spell master who carries a large shield and often casts mirror immage to distract/divert enemy attacks while the fighters flank. He's an evil little gnome, so not as many heal spells; but i like the hurt spells better anyway 
The thief made it to level 8 when i dualed her to a fighter. that worked pretty well, but she could have stood to have gotten a few more thief levels first The Bard is always singing that song, occasionally summoning goons and once a day she turns into a fighter (tenser's transformation) who rivals my actual fighters. I went for versatility in this party. Between 4 players there are 2 clerics, 2 mages, 2 fighters and a thief.
[This message has been edited by Leafy (edited 07-16-2001).]
[This message has been edited by Leafy (edited 07-16-2001).]
[This message has been edited by Leafy (edited 07-16-2001).]