I still keep a couple of "conventional" set ups around for various reasons. King Salmon from the shores of Lake Michigan is a tough thing to accomplish with a fly rod. You very rarely have enough room for a backcast and when you do, chances are you have to worry about people jogging, walking, picnicking, etc..behind you. If it's not that, you have a brutal wind at your face and getting big sinking lines and flies out there can be tough. To top it all off, the best fishing is after the sun goes down which makes it even more challenging.
The other exception is musky fishing. I am usually good to go for about 4 to 6 hours of chucking 10" plus flies to musky but damn your arm starts to get tired after a while. It's nice to take a break and chuck lures that weigh in at solid half a pound