The confusion comes from the fact that there are two types of remote controllers.
Those which connect to the remote control jack on the camera, with a cable (the TC-80N3 is one example, for the better camers, but there's a similar for the smaller ones - ahh, it's mentioned above, RS-60E3), don't need any special setting on the camera to work. Just press the button.
Then there's the IR type of remote control, like the RC-6. They don't work at all, unless you set the camera to remote control mode, which happens to be the same thing as self timer. But when using the RC-6, it doesn't matter if I set my 7D to 10 sec or 2 sec self timer. That's controlled by the RC-6, which has one immediate and one 2 second delay setting.
I haven't tried what happens when using mirror lockup and the RC-6 on the 7D, though. When using the TC-80N3, everything is identical to using the normal trigger button. The RC-6 remote is the only one which allows you to start/stop video recording on the 7D. You take stills with it set to immediate mode, but start/stop video when switching it over to 2 second delay mode.
The RC-6 is also pretty handy in Bulb mode, since it literally converts B to T. You press once to open, then once again to close. No need to hold/lock the trigger button during the entire exposure.