I noticed that most main characters in anime are seems to have the same special trait : they must have some kind of special power (yakikate - solar hands, gundam - newtype, coordinator, naruto - fox demon, sixth sense, esper, etc) which are given since birth or they must be some kind of choosen people from specific heritage,etc.

Those kind of thing in my opinion are just too much, uneducating and could lead to assumption that without that special trait they can't be the main characters / hero. (common people would probably say : I don't have special ability so I don't think I can be special and so why do I have to try hard?).
not to mention that that kind of "special characters" are usually (I said usually, doesn't mean I generalize them all) more lazy in my opinion -because they had special power, they never trained or push much effort to archive something.

I personally prefer the idea of "ordinary people doing the extraordinary thing" like in macross I & zero, gundam ms08 or kaleidostar where the main characters are no different than the others, they use the same mecha/unit (like macross) and they proved themself because their hard training and experience.

another good example here is gai & rock lee in naruto, they train hard and earned their power by "obtaining" it, but in naruto they are just merely a sidekick (compard to naruto or even kakashi) which is very unfortunate because their phillosophy is very good in my opinion.

so what's your opinion about most main characters in anime? do they have to posses some kind of power to be special?

I think that the most important thing is for the main character to be original.
I presonally have nothing against 'special abilities' (especially that in the story I'm making the main hero also have one ) as long as he/she is not unbeatable and the storyline is intresting and not simple.

in my opinion, main characters should be unusual, and interesting, and also appealing. he/she does not have to be super powerful, they just have to be original. no copycats or anything.

It is just common in anime, movies and books for the main character to have something special. It might not be a power but just a strong will, really good luck, or just being really goofy and clumsy. In any case there must be something to make him unique in comparison with everyone else.
I still agree with Rayearth that the example set by Rock Lee and Gai is a good one and it marks a change in anime. Just remember the old Dragonball days when everyone was super powerful and super special and then got more powerful and then more. Nowadays characters have special features that are not all-powerful and they have some flaws as well which makes the story even more interesting.

Quote by DrakI think that the most important thing is for the main character to be original.
I presonally have nothing against 'special abilities' (especially that in the story I'm making the main hero also have one ) as long as he/she is not unbeatable and the storyline is intresting and not simple.

Me too. Also, as long as the main character doesn't annoy me.

most of the romance comedy consist of a totally in my opinion normal character who has the ability to make all the girls fall for him ....but then its usually shown later that he has a caring personality =D but yeah most mains do get alot of powerful enhancement from the start, esp those from fighting series.

there special trait is what sets them apart from other anime character's. it makes them all different. you can't really have fun being normal.

sakuragi from slam dunk started with nothing but the ability to learn quick....
i find this more unique than all the other anime/mange where the main characters is super special :p