When Buffy and Spike are gathering up weapons to fight Glory, Spike assures Buffy that he'll protect Dawn 'till the end of the world'. This is one of those moments James alluded to where he played Spike with soul. Spike isn't BSing Buffy, he means it - and we believe it - when he acknowledges a willingness to sacrifice himself to save another.
There has been numerous debate that behavior such as this contradicts statements emphasizing that Spike pre soul was still evil. Then things get even murkier because while ME may place a lot of emphasis on the a soul, the fans less so. After all, if Spike was capable of doing good without one, was it a necessity?
After re-watching The Gift I'd say yes and no. While Spike was capable of doing the right thing he was still capable of doing the wrong thing (I'd point to Forever when Spike aids Dawn in resurrecting Joyce). The soul is no cure all for evil - Warren and Willow being prime examples of what souled individuals are capable of. But, while Spike through his environment (first the chip, then his love for Buffy) could begin to emulate good behavior, he lacked an internal ability to understand the horrors of his bad behavior.
Yep, Spike was willing, on more then one occasion, to sacrifice himself for those he loved. Yet, he had no regrets or remorse for his past deeds and failed to understand why he was only hesitantly excepted into the fold. The soul gave him insight and empathy. Without it, I'm sure he would have continued to strive to do good and most likely would have achieved it. Then again, I doubt he would have had that expression of complete and total understanding - of peace - as he sacrificed himself for the world.
And on an unrelated note....thanks to saava for some niffty new icons. I don't recall seeing any for Chance before. :)