Hi,
I'm just starting a campaign as a 15th level druid, still in the process of creating a character.
If you are looking for power, here's a few tips:
Wilding Clasps from MoF can be added to amulets and vests to prevent being melded into your animal form - thus you still get their benefit. This means if you want several benefits (Ring of Wizardry, Periapt of Wisdom, Wildshape Amulet, Ring of animal friendship) to be kept in animal form, well, you're going to have to move them into amulets or vests. Note that something like Wildshape Amulet or Ring of Friendship might not need to be kept outside of your animal form to be effective.
Wildshape Amulet from MoF increases your wildshaping ability to that of a druid 4 levels higher.
A ring of animal friendship will allow you to bring around another dire bear (12 HD).
Torc of animal speech allows you to "speak with animals" at will.
Taking 1 level of Shifter will allow you to wildshape into a drow with SR 11 + level (but only while in the shape of a drow!). Use Thousand Faces to look like a human so you don't look like a drow. Taking Shifter also allows you to specify which pieces of equipment meld and which don't, so you don't need wilding clasps.
Taking 1 level of monk adds your Wis bonus to your AC while not wearing armor. For a high level druid, this is significant.
If you want to play something different, you can try the Shifter class from MotW. With 13 character levels to play with, you can be a Drd5/Shf8. Shifter gets you extraordinary abilities of the creature (troll's regeneration, SR, etc.). There's a good Shifter FAQ over on the Wizard's boards under prestige classes. From what I understand, though, it's great for mid-to-high levels, but not that great at high levels (wizard's shapechange is fairly similar).
Verdant Lord (MotW) is pretty powerful too - BAB advancement like a fighter, but you still advance spellcasting level. At 10th level (15th character if you try to do it quickly), you become a plant (and all the associate goodness, like immunity to critical hits). Taking the Wildshape amulet still lets you wildshape like a 9th level druid.
Feats: If you want to cast spells while wildshaped, Natural Spell (MotW) allows you to cast spells while in animal form, but using material components can be a pain. Take Eschew Materials to go along with that.
Other Feats: Extra Wildshape (if that's your interest - note a 14th level druid with Wildshape Amulet gets 6 WS and 3 Elemental WS/day). Speaking Wilshape (allows you to speak to animals of the form you assumed).
If you go the spellcasting route, Spellcasting Prodigy from FRCS is almost essential (+2 to primary stat as it affects spells).
I haven't heard many good things about d20 (non-WotC) stuff, but I don't own any of it either.
Another possible (interesting route) is taking 13 levels of druid, and 1 level of heirophant (though this is probably better for a cleric). Choose "Reach spell" as your power, and all your "touch" spells are now "ranged touch" with a range of 30 ft. Excellent for hiding in the back and healing, or inflicting (which is why it's better as a cleric).
If you're going into Epic Levels, you'll hear the mantra "spellcasters should not multiclass". For every level you take in a class that does not advance your spellcasting, you drop your *highest* level of spellcasting ability. So a Drd14/Shf1 loses the ability to cast 8th level spells. Not too big of a deal if you take only 1 level of another class, but something like Drd5/Animal Lord10 (from MotW - no spell advancement) is significantly different in terms of power. (e.g. summon dire animals 2/day is only a 6th level spell, and a major power of animal lord. But a 15th level druid can actually do this easily!)
If you spend a lot of time wildshaped (note wildshaped druids cannot speak any language at all without the help of magic! this is dealt with in another thread here - you'd need to make a house rule spell, feat, magical item, or ability to deal with it), don't worry about your Str and Dex - they'll always be replaced by the form you assume. Con is still important, for although it gets replaced while wildshaped, your HP are still the same.
Be sure to check out "legendary animals" from MotW. They're much more badass versions of Dire animals - A Legendary Bear (20 HD) gets 2 +27 claws, 1 +22 bite for enormous damage!
That's all I know so far. Hope this helps!
