Here's a workflow I use to work with text files (which for me live in Dropbox, but that's not a requirement).
It has these features:
Create a new text file Query: create {folder to create the file in}, followed by the filename in the resulting dialog
Search across existing text files Query: grep {search query}
Append a line to an existing text file Query: append {file to append to}, followed by text to append in dialog
Prepend a line to an existing text file Query: prepend {file to prepend to}, followed by text to append in dialog
More at http://matthewhealy.net/blog/category/text-tools-for-alfred. I'd love to hear feedback and suggestions.