I′ve totally ignored any reviews and spoiler boards and basically anything except this forum, which seems safe to me
So, I don′t know much about Skyrims new Skill and Perks System.
It′s also been a long time since I played Oblivion seriously the last time.
Same goes for Morrowind, of which I only played a little bit.
So, I′m a little concerned when I look at all the people posting their playstyles here and how they will build up their character, that I might do some dumb choices if I don′t think about it before and that I might loose a lot of gameplay depth because of missing knowledge. For example alchemy, I never really got into it in any game.
So, maybe you want to assist me with my character creation?

I would like to be a kind of sneaky battlethief that can deal some good damage and maybe has some magic abilities.
OR I′ll just be a warrior, I still have to deal with the thought of the mighty Dovahkiin being a mere thief... idk would that feel right? Also I love exploring. A thief might get some problems in the woods...?

Well if I go for the thief, I′d like to try double daggers and maybe train sword ′n shield as well for backup.
Marksman, I′m not sure about this, it′s probably good for an assassin, but I feel this is one of the skills that have to be maxed to be useful, and I don′t know if I really wanna max archery...
Poisoned weapons would be awesome as well, so I′ll probably get into Alchemy. I heard there will be backstabbing perks and that cool kind of stuff. I guess no one would read through a complete list of perks, but are there some that are especially worth mentioning? Maybe some that suit my playstyle well?
Light Armor would be nice, if possible. Heavy Armor could be kinda meh, I love running around fast.
In terms of magic, I think I could add Illusion, for invisibility and stuff, and maybe destruction to deal with pesky melee-orcs? Btw, how will I not svck against dragons if I don′t play a Battlemage/Heavytank?
Does enchanting work well with poisoned weapons? Smith is cool, too... THERE′S JUST SO MUCH I COULD DO
Of course I need lockpicking and pickpocket as a thief, and I always like to max speech, because I wanna sell my stolen stuff for a good price and escape the prison without getting my butt kicked.
So, are my choices decent?
For the race, I think I′d like a Nord, I mean, it′s Skyrim, c′mon.

So, as you want to entertain yourself until Friday anyway, maybe you want to help me to build a decent character out of this information?
Maybe someone could teach me a bit more about the magic schools, I rarely play as a mage, and I never quite read into them....

Thanks you in advance

Basically, the only choice that affects your skills outside of normal gameplay progression is race. You don't pick a class or any major skills. So basically, play how you want and that's what you'll become.

Too much tl;dr in here?

http://elderscrolls.wikia.com/wiki/Skill_%28Skyrim%29

No spoilers in that specific page (though I wouldn't mess with the anything in the wiki that's not perk-related, just to be safe).

You're really vague in your specifications. You could easily take what you put in and make two completely different characters (or even more!) Try to think primary means of attack, secondary means of attack, and then build everything else around it and/or your character.

Am I the only one here who doesnt pick my perks and skills and all before I even get the game? I just play the game and enjoy it and let my character develop as I play

I can′t get any moer precise because I don′t know how the system works in the first place.
Will I be choosing my "main skills" whose perks I will be able to build up faster? Or will I just be able to choose my perks from whatever I want and I get boni at whatever my race is good at?

What im disapointed about is the character creation will be like Mr Potato Head. You can stick on eyes or a mouth, but you cant change the potato.

You mean the visual appearance? I herd they put even more customization options in than in oblivion! They probably just got rid of those options that made your character look like a deformed conglomeration of derp.

Well you can play "jack of all trades" (pretty much how you've got it set up) but you'll be over-all weaker in those skills since you'll be spreading out your experience in each different skill. Also, the game levels you up based upon what you do. So if you're using the bow a lot, it not only increases your level in archery, but it goes towards leveling your character up. In Oblivion, only a certain amount of skills you "pick and chose" in the beginning, when leveled up, went towards your overall level.

I hope this made sense.

Sounds like you have alot of things you want to do, there is only one way to solve that, make multiple characters.
Battlethief? Kind of sounds like a stealth orientated fighter that does some thieving. Maybe hes going to join the dark brotherhood and the thieves guild? Use skills such as archery, one handed, light armor, sneak, alchemy, pickpocket, lockpicking, destruction wouldn't hurt.
You like stealthy exploring? Sounds like you should look into making a ranger. They live in the wilderness most of the time, they prey upon bandits and goblins, they are excellent hunters, leave heavy armor and shields at home, a longsword is good to have for when you run out of arrows for an enemy gets close. They know just about everything there is to know about there is to know about the plants and how to use them effectively.
Pick a place you want to chose as your area and start patrolling. I have personally had 3 rangers, a nord that lives in the jerall mountains, an imperial who lives in the great forest and an argonian that lives in blackwood.
Also you want to do a great warrior for the main quest, obviously be a nord, go with the heavy combat skills, and have some frost magic at your disposal, after all this is skyrim right?