I guess it would depend on what you fish for mostly but for me,its an 8wt.
More than what you fish for, you want a rod that will throw the size flys you plan on using.
A 8wt is fine in many situations, but a 9wt will let you use larger flys.
The wind is a factor in many areas also.
My "5wt" is a 9...sometimes I go down to an 8, more often I use a 10
------------------
"The day after tomorrow is the third day of the rest of your life"
The simpler the outfit, the more skill it takes to manage it, and the more pleasure one gets in his achievements.
--- Horace Kephart