Here's one for you number crunchers. If I want to take a charachter trough TOB and max out on XP, do I have to go solo? If not, how many NPCs can I have with me?

Well lets say by the end of TOB a party of six had 6 million xp each, i get some where around that. A party of 5 should be able to hit the cap, but some of that xp comes from quests that give xp out per party member so maybe not. Playing solo and doing watchers keep you would of hit the xp cap in SOA easily.

You can conceivably hit it if you do every single sub-quest and kill every single monster in the game with a 6-person party. However, a 5- or 4- person team that does most of the game should come close, if not hit the XP cap.

Dundee, when playing Solo, regularly hits the ToB experience cap while in the Underdark.

Solo TOB hit the xp cap in the City of Caverns, "sharkland", but I have neard of people hitting it in chapter 2...

i just started my first solo(sorcerer) i haven't really done anything(first dungeon, circus, stronghold, maybe a couple of minor quests) not even the slavers yet and i'm already level 11 or 12

With a party of six, I fronted up to the final bash with my sorceror 30k (odd) shy of level 31. I started ToB with a party that was maxed out after SoA though this will still see you short of the xp cap.

The trick: my sorc (being the evil, sadistic bastard that he is) had Summon Fiend memorized and used get orgasmic every time he summoned a glabrezu to test out his melee skills. He was crap with a staff so it took a lot of practice!

12,000 xp per fiend x 8 summons per day = lots of xp.

It's cheezy I know, but at least i was role playing.

Another way to max out your party is to go visit...

S
P
O
I
L
E
R

...Sendai's enclave and bash the skulls of an unlimited number of Duagar slaves. This too is cheezy but you might as well get the most out of it while your party lasts.

A party of 6 can max out their XP in Saradush. Just keep killing the Fire Giants.

Actually, they can do it much before Saradush. ;)

From what I've seen from the IE games, they design them so the XP cap is roughly at the highest level a party of 6 can attain from playing the entire game with all subquests, but *without* exploiting respawning monsters.