First of all just let me say that i am a veteran wow player and i was thew kind of guys who liked to create better tech trees over there... and i would like to do the same here.
After I completed the campaign 2 times( 1 on normal and 1 on hard), i think i took the best out of each tree....

Witcher tech tree: only 6 points to unlock the other trees. (you better do Frotitude max over dagger throwing)

Alchemy:I found almost no use in that tree but for the bombs upgrade, an i was constatly using oils and potions.... Alchemist-2 points.

Sign tree: Axii/AArd/ sign damage+1 - 1 point (doesn't really metter in which one)
Quen - 2points
Magic Intensification - 2 points
Magical Vigor - 2 points
Venting-2 points
Igni- 1 point
Yrden- 2 points
Glyph Enhancement / Magical life force - 2 points (didn't decide which is better)
Sense of magic- 1 point (I just love the slowing time magic)
Control over power -2 points

Swordsman tree:Feet work- 2 points
Position - 1 points
Violence - 1 point
Whirl - 2 points
Hardy - 1 point
Precision - 1 point
Invincible - 2 points
Combat Acumen - 2 points

Over all 35 points

This i just a suggestion and a first draft.... I wrote to get some feedback from you experience.... Please say something that could be better and why....

Thank you in advance :)

Update no.1 : position is now 1 point (-1), Magical Vigor is now 2 (+2).

no body want to help? :(

Its unclear to me. Is position making you damage 200% more when attacking from behind ?

Also how about Riposte ?

Is it any good ?

I also took feet work instead , but now i am considering taking riposte aswell.

Yes, position makes u suffer much less damage when attacked from behind.. even though i don't know if i need it know... when i was a begginer i suffered alot in combat especially because i couldn't control every thing properly, but know i barely get hit in the back at all....

also remind me what is Riposte, i have hard time with names...

alchemy tree is probobly the best tree in the game,
you get to upgrade mutigens and you get 5 mutigen slots,

works out pretty nice if you have 6 greater critical effects mutigens and 4 greater strength mutigens

I am confused

Position makes you suffer less damage when attacked from behind, or makes you damage 200% more when attacking enemy from behind ?

As for Riposte , its one that allows you to parry and retaliate attack , and have 50% chance to be fatal attack

I doubt there is a "perfect" build, but mine wasn't much different from yours. I chose Aard over Axii; the time to cast Axii and its failure rate drove that decision. The one major difference is that I maxed out vigor. Having 5 vigor points meant I could enter battle with the (maxed out) quen sign up, throw down a yrden, have two points for aard if I need them, and still a spare vigor left for an emergency quen if my first one gets beaten down.

Frankly, if you max out quen, there is almost no other choice you need to make. I suspect the game would be much harder if you put zero points in quen (focusing on swords and bombs), or only the one point necessary to move past it on the magic tech tree.

Yea, i heared maxed out Quen is pretty potent

it makes you suffer less damage when stubed in the back....

I wouldn't recomend Riposte... in combat you always have to move, dodge and be very mobile, if you parry to much you aren't really mobile, so it's probably a good skill for 1V1, but usually there are much more apponents.... if you don't want Position i suggest you to put it in the more advenced Sign or Swardsman....

Also, if you will notice, i did gave feet work 2 points I you notice, i did maxed out quen..... you have a good point on vigor, but from my own experience 3-4 vigor is usually enough.

Depend a lot of your gameplay style more than anything else.

In swordsman for example. Position is great cause it reduces the damage from behind. But if you have a 'rabbit style' like me (meaning i move Geralt really fastly all along the battle field), this is not that great. You could consider switch one point from position into riposte which is a great aptitude.
Invicible definitly worth 2 points. 20% damage réduction + 100 vitaltity worth the deal.
Whirlwind help with one or two point.

In magic :
Quen : 1 point is enough. when you can have heliotrope, 2 point in control over the power will charge your adrenaline bar in no time.
Venting is nice. But you should considering improving your vigor. 2 in destructive magic. At least one in magical vigor.
5 points in vigor help you casting some yrden/aard/igni with a quen activated.

Axii is great but take time to summon the sign and in front of several foes isn't that great to be honnest. Specifically considering this can botch !

Yes, I saw that you maxed out quen; I meant this as a general statement that any build with quen maxed will work just fine. Any skill that can (a) absorb almost every type of damage, (b) stun attackers longer than aard without pushing them out of combat range, and (c) reflect a large portion of damage to as many as three opponents is pretty powerful!

i have updated it a bit so magical vigor can have 2 points (4 vigor is enough... i have never found myself needed fore more)

Here's mine: http://i54.tinypic.com/o791j6.png

Notice I should be lvl 38 but the cap is at 35.

I thought the two points of magical vigor at the left were pretty useless, so feel free to distribute them somewhere else.

I decided not to go with Impregnation since I thought percentages were better than flat numbers, and 3 more points to get to lvl 2 impregnation seemed useless in the face of +10% extra sword damage and +10% extra armor, and a free 3rd point to distrute somewhere else.

It ended up not being as good as my previous game's stats, at least damage-wise.

P.S. this was my 3rd playthrough, and it was on Hard.

PROTIP: Each point of SIGN INTENSITY adds 25 seconds to the Quen time. This is NOT explained anywhere in the game.

I'll just go ahead and request a mod that removes the level cap from 35, and maybe move it to 40 (though it's probably impossible to get to 39 either).

EDIT: I remembered why I went for percentages... In the long shot, that is, more witcher expansions, damage and armor would be better, and percentages would really shine.

If you want a better endgame build, however, based on impregnation, here's this alternate build I just whipped up: http://i54.tinypic.com/2vdgtoy.png (though I still think impregnation isn't worth it). Place the final two points in Violence and Tough Guy.
I used 3 greater power mutagens and 2 greater strength ones. I didn't find any madness mutagens on this run.

The thing is... i think that the Magic path is much more benefitial than the Potion path... that is why i have gave it only 2 points for the bomb and trap upgrades

Considering the magic path is basically spells that you have to switch between, and that the only necessary spell during regular combat is Quen, the sword should do most of the work.

The alchemy path's Synthesis lvl2 skill basically increases the positive effects of potions and decreases the debuffs.

A Virga potion ends up giving +32% armor and substracting only 1% from 3 resistances.
Rook ends up giving +17% damage. Gadwall ends up at +3 combat regen with no negatives, and so on.

Basically, going up the magic tree means discarding the powerful buff offered by Synthesis (and well worth the 5 points) in favour of spreading out between spells, and having to switch around (or wasting points on magic you don't plan on using!).

With the 2nd build I posted, I killed Phillipa's Elemental in 3 hits. using the following potions: Virga, Tiara and Thunderbolt, using Addan Deith with 3 Ysgith runes.

More damage means less hassle. More defense means less hassle. Fewer spells also means less hassle. It's a win-win situation.

After my 3rd playthrough, I realized I don't need to waste points on venting, as I was merely using Quen as a shield, and Yrden ended up being fine without putting points into it.