My favourite dip is hummus.

I use a recipe I got out of Cook's Illustrated.

Hummus

1 tin chickpeas (garbanzo beans), rinsed and dried
1/4 cup tahini (sesame paste)
1/4 cup extra virgin olive oil
1/4 cup cold water
3 Tbs lemon juice (about 1 lemon)
3/4 tsp salt
1 garlic clove, crushed

If there's time, remove the skins from the chickpeas, it'll make the hummus smoother, but it's not a requirement.

Place all the ingredients in a food processor or blender and blend until smooth, about 2 minutes. Cover and refrigerate for at least 30 minutes to give the flavours a chance to blend and mellow. Can be kept in the refrigerator for up to 4 days.

Use as a dip for pita bread or cut up veggies.