of fate and bloodlines

I posted this at about 3 AM on another thread, but I realised that it's sort of an entirely different topic. Since I'm brand new to this board, be gentle. This is mostly an observation. I welcome thoughts and insight.

The fact that Gollum survived as long as he did (considering the many chances others had to take him out of the picture) actually brings up an interesting question about the role of fate in LOTR. In the movie, Gandalf tells Frodo that Bilbo was "meant" to find the ring, and that Frodo was "meant" to have it. There are references to fate in the book, as well. Remember the riddle that Boromir brought to the council of Elrond:
"Seek for the Sword that was broken:
In Imladris it dwells;
There shall be counsels taken
Stronger than Morgul-spells.
There shall be shown a token
That Doom is near at hand,
For Isildur's Bane shall waken,
And the Halfling forth shal stand."

There is also the famous line that Bilbo shouts out during this counsel, the last bit of which is:

"Renewed shall be blade that is broken,
The crownless again shall be king."

It's always interested me, the emphasis that is put on bloodlines and fates in this story. Aragorn is destined to his end because of the strength of his blood. Likewise, it seems that Frodo has been intended for his fate since before anyone knew that this journey would need to take place.

I tend to shy away from the idea of fate, because it takes away from the heroism of an act like the ones in LOTR, but the fact that Gollum lived long enough to play a vital role in this story does seem to indicate a certain level of destiny. Any ideas?