I usually target Sunfish, crappie, bass, and Carp. Man you wanna talk about fun. Watching a 15lb carp sip a fly off the surface and then scream line off after the set is crazy fun. About filled my trunks (I wet wade) the first time it happened. I use a stacked deer hair fly called a dog biscuit for carp. I tie them in white to look like a piece of bread. Works like a charm.
I have had them bend my 9 foot 6wt into the cork. I toss the smaller stuff on my 6'11" 4wt. Makes a big shouldered bluegill seem like a tank. Since I went over to fly fishing I haven't gone back to my other tackle.
I am thinking of getting a 9wt to go after Northerns and Muskie. God now those flies will be huge!