You wouldn't even need to use a blender if you didn't want to. Simply finely chop those things that need finely chopped and rough chop the rest. If you want a smoother sauce then by all means, add them to your blender.
I also like to use a bit of pesto thinned out with some olive oil, fresh tomatoes, fresh basil chiffonade, finely minced garlic, salt, pepper, and that's about it! I top with either grated Parmesan or shaved Parmesan. Makes a great summer meal or side dish. Basil chicken, or just cooked chicken chunks, that have been allowed to cool, will make this a well-balanced meal.
Anything that calls for fresh tomatoes simply substitute your tinned tomatoes. I like the liquid from tinned tomatoes as it adds some good moisture.
"Count yourself...you ain't so many" - quote from Buck's Daddy