Ah, this thread & poll again.

Only problem I had with the FO3 ending was the quality of it - the dumb choices you were forced to make.
First playthrough, I went along, did sidequests, did the main quest, saw the final movie (~25 hours total).... and then reloaded my earlier save from before the "Final Mission" and ran off exploring the wasteland for another 50+ hours. No problems at all.
I sincerely hope that there's no BS-style DLC. The "more sidequests" DLC were fine, but the "continue the story that has ended" thing didn't really work. Of course, a good portion of that was because of the increased level cap and all the game-balance-destroying crap that went with it (annoying monsters, overpowered perks, too many skillpoints, etc).
I don't even bother installling BS these days when I do a reinstall of FO3 to play it again. It's just not an improvement.