I get enough flanging out of my guitar by switching the pase of one of the pickups. I prefer that to using a flanging effect because there's no hint of 'sweeping' behind the sound.

Some of my amps have tremolo built-in. It's OK, but it only gets used once in a while. It can wear out it's welcome quickly.

Now, chorus is a very versatile thing. You can set it up so that it's very subtle, filling out your tone without being easily identified. A stereo chorus feeding two amps can gently push your head off of your shoulders and roll it across the floor! :D