That can be a long time if you want your original class to be high level. I usually try to dualclass out at 5th-7th level fighter so they're not vulnerable too long.

It depends on what that single level of fighter can get you. I would stay with fighter until I had specialization or master level in one weapon to get good attack bonuses. Shields are better later on , but always helpful.

If I was playing myself , I usually leave the healing to other party members , usually a cleric and a druid to get spell variety along with a mage for timely firepower. Add two heavy warriors to keep the uglies busy and a thief for stealth , trap removal and unlocking chests. So I generally keep everyone single class , that way they reach the better abilities , spells and powers sooner on in the game.

I don't remember how many levels it takes , it's been too long. I might have to go and reinstall Baldur's Gate! Then I'll never get anything done.

You get to pick a couple of proficiencies at character creation and then every few levels or so you get to pick another one.
p. 92 manual

Level of Proficiency  | Points spent | Bonus to Hit | Bonus Damage | Attacks/Round
Proficient                    1              0            0                1
Specialized                   2             +1           +2               3/2
Master                        3             +3           +3               3/2
High Master                   4             +3           +4               3/2
Grand Master                  5             +3           +5                2

Only fighters can spend more than two proficiency points on any single weapon class proficiency (not rangers / paladins) . Warriors get an extra attack at 7th level.

In BG2 you start at level 7 or 8.

Speaking of the fighter/cleric:
i'm pretty sure that in BG 1&2 you will be restricted to cleric only weapons, so no long blade. You should focus on mace weapons instead.

The fact is that BG1&2 use the 2nd edition, NWN the 3rd, which gives your more chances to make powerfull characters, but also less credible characters (es. paladin\sorcerer). The 2nd edition restricts you more but enables, IMO, only "realistic" choices, which is good.

As for a good character, i prefer to not multiclass in 2nd edition games and usually go with a straight class. In BG2 i'd go as a sorcerer (at later levels you simply are a weapon of mass destruction ), in BG1 as anything but mages (too weak and too few hp at those low levels). Interesting multi/dual classes would be fighter/rogue, fighter\cleric, fighter/mage.
This is of course just my personal opinion

I disagree, in some ways. With dual-classing you can effectively get a level 28 character (or so) in BG2, because of how the way the XP adds up (and the fact that different classes level up at different rates). In 3rd ed most classes get their good abilities quite late, so it's usually not worth it to train several classes (the expection being prestige classes, which are pretty good at lower levels, and often requires two or more classes trained beforehand).

You can only multiclass "pure" classes (except for gnomes who become illusionists if multiclassed with a mage) (and only dualclass to a pure class). Though a kensai dualclassed to mage is one of the most powerful combinations in BG2 (also most cheesy). Also, you can have specialist mages in BG1 (they are not that great anyway).

But yes, it's usually better to make a new character in BG2. Esp if you have a cleric, since the cleric kits have (almost) no drawbacks but plenty of bonuses (same goes for fighter->berserker (almost no drawbacks) and the thief kits).

My favourite class by far in BG2 is the sorceress But it's probably not a good "first game"-choice as it's pretty unforgiving to mistakes (you pick spells, and you are stuck with them). If you have the expansion, the wild wizard (oslt) is pretty fun

I also like the assassin a lot (its poison attack is much better than described in the kit description). It could be dual-classed with a fighter to get a pretty lethal poisonous whirlwind attack

DELETED

forget it... you ware aware of tutu already...

I've found a pretty funny exploit, make a wild mage and use the spell sequencer (or whatever it's called) you know, the spell with combines two spells, anyway, combine atleast two Nahal's Reckless Dweomer and cast it, you know how you get a list of spell to cast? well, usually it disappears after one spell has been cast, since it's two i figured that i should be able to cast two spells, but after spending the second one the list didn't disappear.. you have unlimited spells of all levels! Mohawhawhaw..

The downside is that since you're a wildmage you'll always live with the possibility of getting a cow in your head every time you cast a spell ... and as the enemy has no chance of winning (unless your wild magic goes wild) the game becomes pretty boring.

have anyone else found this exploit?
btw, i don't know if this has been fixed in the latest patches.

Consider there is an XP cap, and that each class has different xp requirements you should calculate what level in kensai will leave you enough exp to be a +1 (or more) level mage.

It is true that many classes get good traits on higher levels, but the 3rd edition allows you to multiclass in unrealistic and extremely unbalanced way, IF a DM doesn't prevent it. Check this
Another common example is the 1paladin\sorcerer so abused in NWN, you basically get huge saving throws bonuses from your paladin level and all the destructive power of the sorcerer, all of this playing a character that has to reason to exist!

Yes, if you fall in love with your character
Seriously if i where you i'd just start by playing BG2 (which is what i did, since at the time i wasn't able to get a copy of BG1), which is far more balanced and entertaining than BG1

BG1 is defiantly a good game to play. And as i understand it, it's a bit more in "the spirit of AD&D" (low level cap etc, no uber-characters). There is also a bit more exploration in BG1. I still prefer BG2 though.

I was speaking of actual content (and that's why i like the Icewind Dales series less, due to it's lack of story)

Icewind dale is inferior to BG1/2 in almost every way (imo), but it's still pretty fun. It's pretty much just a dungeon slasher/burner/maimer. Get it, play it after you are done with BG1/2