I am an A grade SK and I solo quite a bit, so I use +4str -4 con, and +3 int, -3 wit, +2 int, -2 wit. I wear Majestic Plate Armor and use a DLE with health.
The str. helps very much while soloing, I can kill much faster and you dont really need HP very often. The con you dont need to much because the Majestic gives you stun resist and I hardly ever will be stunned. The Int. is good because with +5 to int. I never miss a Hex, Powerbreak, or confusion and my Drains give me more health. Also, my LS paralyzes more often. At the moment my paralyze is 78% on mobs, and 25% on players.
The reason i put health on my DLE is just because I do occasionally PVP and since SKs have low CP you do need a bit of life.
Some ppl would argue NM over Maj, well maybe... but I get stunned, being DE and all 10x more than I am slept or held... and if you're tanking whats it matter if you're slept or held?