Cubes of baked tofu dunked in BBQ sauce, Teriyaki, Etc, speared with a toothpick.

Pretzel Bites?

Maybe an assortment of salumis, if you/your guests want a little meat. Easy fruits too like strawberries or grapes if in season. And some sliced baguettes from a local bakery. Have fun!

david chang's pork belly buns, cut in half! bacon wrapped potatoes in toothpicks with spicy may!

oops. spicy mayo!

what about roasting your own nuts?? You can make different seasonings- sweet/savory combos.

How about little cornichons (or other quick pickled vegetables) or deviled eggs (you could do a variety of fillings)?

Also, if you're doing nuts, David Leibovitz had a great spiced nut mix recipe (nuts, cocoa, brown sugar, butter, chili powder...) in his book The Sweet Life in Paris, and I'm sure you could find something equally good/simply online.

--polenta squares topped with chopped sauteed mushrooms
--frittata cut into squares
--cheese, salumi, other cold cuts, baguette slices
--roasted red potatoes, quartered, with saffron aioli or romesco sauce
--radishes, butter, salt
--crudites and an interesting dip
--strawberries! in season now
--blanched asparagus spears
--gougeres

Try my favorite go-to appetizer: Greek Salad Skewers. Layer a bite-sized wedge of english cucumber, small cube of feta, 1/2 of a cherry tomato and top with half of a kalamata olive... stick a toothpick through them all and stand them on a platter. You can make as many as you like earlier in the day. Drizzle a Greek or Italian salad dressing over all just before serving. I'm actually fond of Wish-bone Italian but make your own if you have a good recipe. Just a bowl for the discarded toothpicks and you're set. Have a great time! Oh... and let us know what you served. I know I'm always looking for good ideas.

Why not make your own hummus? Roasted Red Pepper Hummus is one of my favorite, but plain is delicious and easy to make too!

Bruschetta is also easy finger food (top it with a traditional tomato-basil-garlic-olive oil combo or anything else, really).

Everyone is saying strawberries and they are right - best party food ever... otherwise fruit salad kebabs are great: pineapple chunks, peaches, apples (not bananas!), seedless grapes on a skewer.

bruschetta (martha has a couple of recipes here: http://www.marthastewart.com/article/bruschetta-recipes), guacamole with chips, and tiny handheld spanikopita triangles are my favorite finger foods.

martha has a great recipe got grapes that are covered with a cream cheese/ Blue cheese mixture and then nuts. You can make them ahead. It's in her entertaining book

@farmersdaughter - gougeres are the best and when i make them, they always get compliments. i mean, really - cheese puffs with salt? yes, please! this is the recipe i use: http://smittenkitchen.com/2006/12/just-a-few-bites/

and these are also well-received:

cheese straws: http://smittenkitchen.com/2009/06/cheese-straws/

and these, or other flatbread, cut in squares: http://smittenkitchen.com/2011/01/pizza-with-bacon-onions-and-cream/

and, this sounds super weird, but its delicious and people think you're a star at thinking outside-the-box: http://smittenkitchen.com/2009/07/cantaloupe-salsa/

have you ever seen those fruit skewer gift basket things people send? I made one for my SIL's baby shower and it was the easiest/most impressive thing I've ever made. People thought I'd spent tons of money on it etc. but really it was just a pineapple, a bag of grapes, strawberries and some melon.
my other crowd pleaser (EVERY time) is cream cheese/hummus with a squeeze of lemon and pepper. Serve with cold cooked tortellini for dipping. People will go mad for it, have reserves.

sorry, I meant to say pesto instead of hummus. I container pesto, 1 container of cream cheese, a squeeze from a slice of lemon and some pepper on top

These Blue Cheese and Fig Savories are my go-to party nibble. They are easy to make, but different. And they were a Food52 winner! http://bit.ly/caGbs1

This is one of those times the Kitchn's policies on reader questions kind of bugs me. Why not do the research yourself and put up links? Since links don't work in the comments, it makes it a pain if ALL of the ideas are in the comment section. Sigh. I guess I'll have to do a ton of copy/pasting.

How about these mini pizzas: http://www.seasaltwithfood.com/2011/03/easy-mini-pizza-cups.html

or Vegetable pizza: http://allrecipes.com//Recipe/vegetable-pizza-i/Detail.aspx

I've made very similar items and they are a big hit!

Definitely edamame. Make sure you have bowls for the empty shells.

@sipalittletea, links do work in the comments. You just have to use the proper HTML markup to make them work.

A few people have mentioned skewers. I find that people get excited about anything on a skewer -- caprese salad, grilled halloumi, jello shot cubes, fruit...

Basically, always put something on a skewer. World Market has these two kinds that make a great presentation.

Any kind of cream cheese-style dip is awesome. I myself am addicted to pretzel sticks dipped in veggie-style ranch dip (not ranch dressing). You can buy it (I favor T. Marzetti's) or make your own. Fresh mozzarella pearls wrapped in basil leaves and stuffed into cherry or grape tomatoes would be awesome. Cut fruit with fruit dip (cream cheese, marshmallow fluff, and orange juice) is also lovely. I made candied nuts for a Christmas party this year and they were fantastic, as was the chocolate bark I made (melted semi-sweet chocolate chips in a quarter sheet pan lined with waxed paper and then topped with chopped dried fruit, sliced almonds, and sea salt - divine!). Chocolate like that would be good if you're serving red wines or oatmeal stouts.

Mini quiches or pies are another option. I always cheat and buy refrigerated pie crust, line muffin tins, then fill and bake. They look adorable and taste pretty good too.

I find however that most people are really quite pleased with the basics.