There are many thousands of day lily varieties. If the blossoms in different parts of your yard seem identical, then the size difference is probably due to the amount of sun, how crowded the clumps are, differences in soil, availability of moisture, etc.

http://en.wikipedia.org/wiki/Hemerocallis_lilioasphodelus

That looks like the old "Hyperion" which was introduced back in the mid 1920's.

Profuse bloomer; long stalks give the appearance of shooting stars when against a green background. The gardens on my property have had "Hyperion" since the 1930's and they never fail.

Thanks Shadey, I do believe it is lilioasphodelus, Lemon Lily. It does have the long leaves that my other lily don't have. It also has a scent.