Could you use a library/dining room? Great suggestions when you do a google image search.

Can you define your idea of casual a bit more? For example, since you don't have furniture yet, what type do you see in the room? What style are you drawn to? You mention wainscoting and buffets as what your mind goes to but say they don't fit your house. Those 2 things can have a very formal or informal feel so I wouldn't automatically dismiss them. A bit more information about your house would help as well since you feel wainscoting and a buffet don't fit the vibe.

I had bookshelves and a small office corner in my dining room. Not a messy "project desk" kind of thing, just for letter writing, bill paying and computer surfing. Also my cookbooks and nature books and other fun things on the shelves. My stereo was in there too, lots of fun tines going on in the background. Another option is a baker's rack or wine bar (if you're into wine, we are, a coffee bar would be similar) or a station for whatever it is that you are into. My current DR has a little tea station. I've always thought fish would be fun but I don't want to clean the tank!

The room is 12x14, only dining space in the home :). So, it WILL be used to eat in! House is open-concept kitching/living (35 feet from one wall to the other!). Dining is adjacent to kitchen. I don't know what I want, and that's the problem- but I feel like I"m heading toward "grandma's house" when I think of dining rooms... where could I find ideas of what a mroe modern (meaning updated) dining room looks like? Fewer doilies and heavy ornate furniture ;)

Or "contemporary dining room" or modern dining room, etc.

If you want a buffet and some storage, consider adding the same lower cabinets and countertop that are in your kitchen. That would help the DR feel more a part of the kitchen. Having the same flooring would also add to the feeling of continuity.

I think chairs that are lighter in look than heavy, traditional dining chairs can help -- open back, smaller scale, etc. like in the example photos above.

A photo would help. An idea of what pieces you want to keep and what pieces you want to save would also help us help you.

That's kind of what I was thinking - that in your mind DR = heavy ornate furniture but there are SO many other options that are young and fun and anything but stuffy! Some great examples above. Again, knowing a bit more about what you like, types of furniture you already have and maybe what your kitchen cabinets are like will help get more suggestions directed towards your taste.

Here's my dining room. It's the only space we regularly use to eat (breakfast nook has been converted to art nook in our house). It's not exactly magazine worthy, but it's pretty casual I think.

(Ignore the living room stuff in this picture, it has mostly changed.)