don't forget

because : naze ka to ieba (sry i don't have hiragana on my PC >.<)

we use that one in my class sometimes.

Thanks for the comment, Hayatokun. You're saying there is no difference between ので and から, other than formality? My professor when I lived in Japan explained to me a bit about how one carries a different implication than the other, but I don't really recall. Was she wrong, am I full of it, or is there actually a slight connotative difference?

から tends to be spoken where ので tends to be written.

I was told too that there is a slightly difference. It was something like ので is more a consequence and から a reason...or something like that. If I well remember something like ので=though and から=because.
I really don't recall it, even because when they explained it to me I really didn't catch the difference and thus being using them as if they are the same.

Yeh, it also has that too... kara is a joining word, so - 私がひまですからつまらなくなってしまいます。which is similar to the way you would use が in 私はひまですがまだたのしいことがあります。so really it is a middle sentence thing... the ので is more of a relative clause type of expression　私はいじわるのでだれも私がすきでわありま� �ん。 so it doesnt split the sentence as such in this case, however, it makes the reason and the cause all in one sentence...
however, just dont think about that too much, just remember, that kara and node are used in almost the same way but one is more formal than the other, and they can both in theory be used after the result.

I remember a bit more about the lesson the professor used to explaint to me. She talked about how when you are late to class and explain to the professor:

バスが遅かったから
バスが遅かったので

that the blame is placed implicitly on different causes—one is you and the other is the bus(driver). Maybe I'm getting the "sounds like it's your fault" wrong and it's something else. But the explanation of から as linking and ので as consequential rings a very muffled bell in the back of my memorybox.

To emphasize your reason, you can use "なぜなら" or "というのは" after the main sentence. I often listen foreighner use "なぜなら". It would be fit English language structure (I mean it does not sound natural Japanese).

Because Japanese language has no direct coresspondance with the word "because", some time you can throw away the ".... because ...." structure. I mean "<MAIN> because <REASON>" structure would be realized in various styles.

そのお人形を買ってあげたのは、あなたが欲しいといったからなのよ。

And, also

あなたが欲しいと言ったから、そのお人形を買ってあげ たのよ。

has enough emphasize on the reason (I think).

RadioKid, thanks for the input. I've taken it to heart. I'll stop trying to imagine there's any sufficient-to-matter difference between ので and から.