I was asked many times about specs what im using on different classes so i think it can be useful for newcomers and everyone else
The classes which i am most experienced:
1) Necro
http://goo.gl/QVYoIB - tribrid, best self-heal
http://goo.gl/TcQnxf - nightfall+general, best defence
2) DT (i use only S&S specs)
http://goo.gl/oTBGYJ - minigames, healthtap on Leech Life
http://goo.gl/4yCciF - dark hand, nearly same as previous one but more useful in duels
3) BS
http://goo.gl/c6kqwO - silence, good anti-mage and dps spec
http://goo.gl/Kdd37U - bubble one, nearly same as previous but with bubble
http://goo.gl/US1ujk - mutilation spec, very high dps and anti-melee combo Bewilder
4) ToS (only specs with Stormfield)
http://goo.gl/JKHwDe - very large set of defensive skills and cc
http://goo.gl/q6mVbU - bubble spec
5) HoX
http://goo.gl/YZZ1ra - standart possession
In avatar there are a lot of varitions, i think 2 will be enough
http://goo.gl/s4qRLj - dot-pillars+insta debuff
http://goo.gl/VJVXg9 - awesome anticc
6) Sin
http://goo.gl/5bazaU - standart avatar
http://goo.gl/LSNe0W - standart lotus