The only suggestions I would make, are to stay away from specialty lines like "Nymphing" specific or "Streamer" specific lines. They will not cast the way you want them to. Second, stay away from beginner lines or bottom shelf lines. Regardless of the brand of fly line, always spend the money and upgrade. Third, depending on what kind of dry fly fishing you do, it is imperative that you ask your local fly shop what kind of line taper is best. For example, I hardly ever dry fly fish, but when I do I cast very large stone flies and I prefer shooting tapers versus a double tapers. But, if you want someone to just drop a name for you, I will push RIO more than any other. Dollar for dollar, they will not disappoint.

P.S.
I have in the past bought fly lines based on others opinions at local fly shops and hated the lines. No one can understand completely what you want unless you are very specific with what your needs are. Good luck.
Lou