Ah yes, filtering the wort. I too have been struggling with this dilemma. If I am brewing a style the only has some bittering hops, such as a stout, I don't worry about it and transfer the whole kettle's contents into my Stainless Steel conical fermenter. But, if it's a heavy hopped IPA, then I have tried different options:
1.
Put hops directly into the kettle
Good: Great for maximum contact. No additional parts to cleanup.
Bad: Creates a lot of sludge at the end -- even if I whirlpool. Plus, if I run the transfer through a hop sock or my fine mesh hop spider filter on the way to the fermenter, they tend clog quickly. I also end up catching a lot of the whirfloc or irish moss, unfortunately.
2.
Put each hop addition into their own mini hop sock and then toss those into the kettle
Good: Greatly reduces the amount of hop sludge at flameout. Whirlfloc or Irish Moss can flow around freely and not get filtered out during transfer.
Bad: Not getting maximum contact. Possible chance of nylon hop bags making contact with electric element and melt. Also more little things to clean at the end of the day.
3.
Put each hop addition into a submerged cylindrical stainless steel mesh hop spider (like this one)
Good: Greatly reduces the amount of hop sludge at flameout. Whirlfloc or Irish Moss can flow around freely and not get filtered out during transfer.
Bad: Severely restricts hop contact with wort since they are stuck in a tightly packed "hop jail". Although I will often pour some hot wort through it during the boil in attempt to "flush the good stuff out into the open". Also a pain to clean.
Lately I have been doing #1, but I might revert back to #3 since I see a lot of brewers doing it this way and IIRC, Brulosophy said there was no preceptible difference with method #3 vs #1.