The current 80 badge shaman trinket is crap, the 70 trinket is better. Hopefully Blizzard fixes it in a future patch, but basically it doesn't proc enough (45 sec internal cooldown) to be any good at all.

Obviously the gear from naxx25 is some of the best you can get in the game, so from that perspective its nice. You absolutely don't need it to clear all the current heroics however. Its fun running once or twice in a good pug, its horrible in a bad pug. I prefer to run my guys solo through it, since there are a number of "trick" bosses, and unless you are running with friends its kind of weird to roll 3-5 times on dropped items. I've cleared naxx25 on every one of my guys multiple times, and every single time I've been the only ele shaman in the raid (or resto in my resto case). It pretty much means all mail=mine, which is nice. I'm on a very busy server though and there are 4-5 naxx25 pugs every night.

The heroic violet hold trinket is nice in addition to the badge trinket, obsidium sanctum25 drops a very nice trinket, and don't forget the darkmoon card trinkets. The prisms (i think) deck gives a card that gives +100 spell power and a 1200 mana pot every 5 minutes, which isn't too bad (the 100 spell power really is the good part). I made one for two of my shamans, and it only cost ~500g each to buy the various cards and assemble it myself.