I like to provide juices (not purple grape juice, though

) like white grape juice, Juicy Juice in 2 flavors (if kids are about),or apple juice. Milk is good, too.
For the taco bar I would get mango, pineapple, guava. Of course you could do a smoothies buffet (although I think this can be more work & is a potential MESS risk factor

) have a friend bring over her blender so you can get 2 going at once.
Iced teas & flavored lemonades are great, there is such a variety! I like to offer local honey, 'natural' sugar, Splenda, Sweet 'n' Low, good ol' white sugar, sliced lemons or other fruits.
It's so thoughtful to make sugar-free drink alternatives available & water, too.
Some folks might want coffee, hot or iced.
Love the sangria idea! It is so colorful & simple to make.
Or a alcohol free punch--adults can add their own favorite enhancer individually
I make an ice ring in a bundt pan, lining up sliced citrus (lemons, limes, oranges--goes with my favorite recipe & will work with sangria, too). I make it out of the punch, so the ring does not water down your punch bowl.
Or go for the all punch ice ring & float some pesticide-free roses or nasturtiums on top. Be sure to check out, some flowers are poisonous! don't want to go knocking off the guests
In dining, I think you can have the most easy, simple food & if you dress the table with some flowers/greenery, plate the food pleasantly, it will look like you slaved for hours!
Jean