Rambo,
As Mark said, start with a 3 weight floating line.
Your next question should be: Weight forward or double taper?
You have a 3 wt rod that is 7 ft 6 inches, not a rod for casting long distances. I assume you got this rod for fishing in small streams or going after 'Giggle Fish' Bluegills and such.
If you are going after trout in a medium to small stream then a double taper would be a great choice. It allows for soft presentations of the fly, something you need in when fishing small pocket water.
If you are going to be casting Crappie Candy type flies, then maybe a weight forward would be your best bet to help cast the weight of the fly.
As for the leader, a 7.5 foot leader would be good for the trout, adjust the size, 6X or 5X or 4X according to the size of the fly. If you are using it for Bluegills and such then a slightly stiffer leader, like a 3X or even a straight 4 or 5 foot piece of 5 or 6 pound Maxima is all you need.
What type of fishing are you going to be doing with that rod?
Larry ---sagefisher---
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