any simple, nutritious, dip recipes? I have plain greek yogurt, low fat sour cream crudite and a well stocked spice rack...?

Try Tastefood awesome recipe for Sriracha yogurt sauce.. You can find it on her recipe page for 'not your toddlers carrot croquette'
http://www.food52.com/recipes/9765_not_your_toddlers_carrot_croquette

I like yogurt dip mixed with a couple of tablespoons of tahini, a squeeze of fresh lemon juice, lots of chopped parsley, and salt and pepper. I leave it thick for a dip and thin it with some warm water for a dressing.

I use Greek yogurt all the time for dips. Mix a 5 oz cup with several tbsp fresh chopped dill and 1 tbsp chopped scallions. Add salt and pepper to taste. It's great with some za'atar stirred in, too.

When I was catering, one of the most popular dips we served with our crudite basket was a Soy-Garlic-Wasabi dip. We never really had a recipe for it. just finely chopped a couple of cloves of garlic and stirred them into yogurt or sour cream (your choice) along with 1/8 teaspoon wasabi powder. Then we shook in enough soy sauce to make the mixture a strange shade of beige and tasted. Maybe a bit more soy sauce.

Neve figured out why, but it was always the first dip dish emptied.

Here's a link to all the entries in the recent "Your Best Dip" contest. Have fun!
http://www.food52.com/contests/209_your_best_dip

Do you have any Cavender's spice? (A premix Greek seasoning).

It's great with yogurt as a dip.

Depends on the application...veggies, bread, chips..etc.
A caramelized onion and touch of beef stock crystals makes a french onion dip.
And Sasha's suggestion takes that to a very good level!

If you want really simple, try making a raita or tatziki kind of thing: grate a cucumber and then squeeze as much water out of it as you can, add to the yogurt and then spice it: salt, a bit of chili, garam masala, etc.

Here are two of my recipes for vegan dips:

http://verdantkitchen.wordpress.com/2011/02/16/live-streaming-raw-vegan-blue-cheese-dressing-its-easier-than-it-sounds/

http://verdantkitchen.wordpress.com/2011/02/07/the-obligatory-superbowl-dip-why-willy-wonka-would-approve/

I'm a big fan of this spinach yogurt dip, with caramelized onions - I cooked it for my Afghani meal. Very healthy and tasty.. and easy! The picture isn't the greatest, but the flavor is wonderful.

http://globaltableadventure.com/2010/02/07/recipe-sabse-borani-spinach-yogurt-dip/