Skills - Winter

You must really, REALLY, advocate "cyber garbage cleanup", as they say. Anyway, apart from the apocolyptic events that triple posting is obviously ushering, i'll confirm that lightning spells themselves don't have base armor penetration, or Lightning Surge would be used more.

One famous Combo is Winter+Greater Conflag+Drydar's Defences+Frostbound armor. USED to sucessfully turn all damage (chaos, shadow, holy not included) into cold damage. Now, however, since spirits have been considerably nerfed, I don't think it works. The triple post is only mildly annoying. The lack of common sense is what gets me. It's like standing in someone's way, looking around, going, "Oh, oops. Sorry, didn't realize I was in your way.", and then sitting down and making yourself comfortable.
To add even more insult, 'oops' has as many letters as both of his other one-liners combined.

Anyway, on-topic:

Winter is most commonly used in the final PvE mission. Either the monsters are resistant to fire, or vulnerable to cold, I can't remember really.
Another PvP that many people have come up with at varying times is the one listed in the mini prima guide you get for pre-ordering-
Winter+Greater Conflag+Mantra of Frost

Winter is still OK, and narrows down a lot of options for you even without Greater Conflagration, and cold resistant armor isn't all that commonly worn otherwise.
An elementalist will know what elemental resist to wear, a mesmer will know which Mantra is applicable (even if physical+elemental isn't cold, all elemental will still be), and a necromancer could use a spell like Spinal Shivers.

Forgive me if I sound rather cranky. Putting explanations aside, I'll explain my earlier post. One of the newest updates limit the number of spirits you can have on the field to one per attribute (Wilderness Survival, Expertise, etc). Both Winter and Greater Conflag are found under Wilderness Survival. Haven't played with spirits since the update much, so nice to know.