Is there any hope of redemption ...?

[greyhavener]

It almost seems as if refusing to align with evil is more grounds for redeption in these tales than consistently aligning with good.

Boromir had no intention of aligning with evil and repented of the idea that he might use the ring for good before he died. Gandalf and Galadriel were tempted by the ring with motives similar to Boromir's. Boromir acted on this temptation, but because his motives were pure he was able to see his error before it was too late. I see this rejection of evil and his final submission to a plan other than his own (Aragorn's kingship) rather than his act of heroism as his redemption.

Gollum was so enamored with the ring that he didn't care what alliances he had to form in order to have it. He didn't want Sauron to have it, not because he was evil but because he wanted it himself. I don't see his act as an act of redemption, but of selfishness that ultimately resulted in good without his intending it.

Wormtongue similarly was willing to form whatever alliances necessary to achieve his goal.

As for the other hobbits and men who aligned with Sauron and Saruman. Each could have chosen otherwise. We know within the community of Hobbits there were those who refused. Presumably the Southons, Dunelings, et al. there were also those who stayed home. Jealousy and vengence are hardly noble motives whatever the deceit that entered into their decisions. I seem to remember that after Sauron was defeated some men expressed regret and received mercy from Aragorn. (Am I dreaming here, I don't have time to look it up this minute.)

Saruman, to me, seems to be the most utterly irredeemable because he knew exactly what Saruon was. He knew exactly what the ring represented. He knew when he gazed into the palantir and when he bred his uruk-hai that he was turning his back on everything he had been sent to do.