I sit down every night and set the metronome to a random tempo. This has improved my feel dramatically, and I have no trouble playing without one. I can't just start playing "80 bpm" off the top of my head, but if I have a click I can play to it. There are people out there who can, though.
I find it's a lot easier to actually establish a groove when you have a band to play with and you have some reference for time, other than just yourself.