Pbartender said:
According to the SRD, an Iron Golem's Challenge Rating is 13. Your character (and your fellow adventurers also, I'm assuming) is level 17. Using appropriate tactics and resources (ie, your druid and his wildshape ability), that encounter should be a cake walk.
I don't really why you are so surprised that your character single-handedly and easily defeated a creature meant to be a 'moderate challenge' to a party of four characters who are four levels less experienced than he is.
Sure, for the whole party it was easy to hack that golem into bits. My problem is: the druid could have done it alone as well. Golems are immune to most spells, so the two wizards couldn't harm it. It has DR 15/adamantine, the cleric and the paladin have no adamantine weapons (the cleric has a +3 bastard sword and adds +12 damage per hit, attack bonus is 24/19/14; the paladin wields a holy avenger longsword, dealing 1d8+12 against a neutral creature, attack is 28/23/18), their damage done was almost nothing. If this four PCs would have engaged that golem without the druid, they would have been slaughtered or at least forced to retreat. Seems to be quite bad for a CR 13 encounter.
@ Xavim: Good points, but I could buff that druid as well

Granted, in a spellcaster duel, the druid is in trouble unless he has a lot of good luck. Hitting a fighter or barbarian is not a big deal, because AC does not improve with level... My druid is horribly underequipped at level 17 (no magic weapons, vestment of AC +6, large darkwood shield +1 + death ward, ring of protection +2, periapt of wisdom +6, bracers of health +4, ring of counterspells, cloak of resistance +3, wilding clasp, some scrolls, some potions) but that seems to be no big problem thanks to spells and wild shape.
@Thanee: Yeah, it was just one...but I fear there will be more.

The DM will surely set up challenging encounters from now on. Otherwise, as Pielorinho said, the druid's tactic will be boring. The silent
Dimension Door was the way an enemy wizard used to escaped the grappling druid.
Freedom of Movement would also help to avoid being grappled. But it would be boring if each opponent has the option to use a silent DD or FoM (magic item, spell-like ability).