Food processors are just as good for smoothies, soup, sauces, and so on, I find. And on top of that, they can do things blenders can't, like juicing citrus, grinding vegetables into "grains", and Essene bread dough. Or do I just have a crap blender?
I find that my blender is much better for pretty much any liquid or semi-liquid that I want to get totally smooth. But my blender is better quality than my food processor--and I use them both every day.
If you're happy with your food processor, then I don't think you're really missing out on anything.
Like ambiguous, I find that blenders are necessary for making things completely smooth (smoothies!). I only use my food processor when making banana ice cream or if I'm grating a large amount of something. Otherwise the blender works just fine.
I don't have a food processor, and a blender gets me by just fine.
Technically I don't have a blender either, had a little incident with pineapple juice and an unsecured bottom. Cheap $20 blender from Wal-Mart; say what you will about a vitamix or blendtec, it may not have been awesome(couldn't handle ice, etc.) but it got me by and lasted for years with solid use(and only died due to 'user error' I guess). Though I will be upgrading to the $60 or so range at Bed Bath & Beyond after Christmas.
But I think you can get by with one or the other(technically without either, but having one definitely makes raw easier and more enjoyable imo), both may be nice if you have the kitchen room and can afford it.