darkSpyro

What is your favourite upgrade path for any Skylander?

Since you have no specifics, I'll give one.

Stealth Elf.

I use the Forest Ninja path because of the scarecrows. With enemies like the Kaos final boss, you can set up a trio of scarecrows wherever he is about to land, and they attack him repeatedly while you dodge his attacks. I can defeat the entire boss battle with just her using this method.
My little brother chose the Pook Blade Saint path because he rushes into battle headfirst, and the knifes help attack more often.

Honestly, it just depends on which path you like more, and what type of gameplay style you prefer.
I honestly prefer dodging attacks and creating things to fight for me, such as Sonic Boom's babies, or Pop Fizz's purple potions

cool. Any others

Undead Defender Chop Chop. Broken Wow-Pow, unique angle on offense/defense that no other character can approximate, and he stuns. The path transforms a horrible character (the worst in S:SA by far) into a powerhouse who stands shoulder to shoulder with the game's true best.

Flameslinger/Marksman
Hot Head/The Burninator
Ignitor/Soul of the Flame

These three are tied

I love on the eruption path! He takes ALOT less time to erupt and on the other path the lavaballs are not to aimable, and bouncing lava REALLY?!