Lots of people listen to TanTalk. In fact, it wouldn't surprise me if more people listen to The Tan Talk Radio Network than listen to The Fan. ;D
MsMusicRadio, there are a number of variables as Frank mentioned. But if you have two transmitters, one with an output of 250 watts on the AM broadcast band, and one with an output of 250 watts on the FM broadcast band... and if you gave them both optimal antenna systems, I would argue the FM signal would always travel further locally. There is so much noise on the AM band anymore, and from experience I can tell you, 250 watts doesn't go very far (locally) on the AM broadcast band... especially at night. Of course, 250 watts can talk worldwide with the right conditions, but again, there's so much noise on the AM band, you really need more than 250 watts to be heard above the noise level. Not that anyone cares, but I've mapped 1340's nighttime signal in my car, and it's really pretty good for a 1000 watt graveyarder.
So again, in conclusion... I say the 250 watt VHF signal wins every time, hands down...