I like the idea that Spike stayed in LA so that he could grow as an individual more than the idea that he stayed because he was afraid that he couldn't top his bix exit, which always seemed kind of petty and wasn't very fair to Buffy, like she would wrinkle her nose at him and tell him that his death was the highpoint of their relationship. I can more easily accept that Spike wanted to see what he was like with a soul, without the baggage of Buffy or the Scoobies or Sunnydale. However, I have to admit that I always have trouble accepting any reason for Spike to stay in LA - I usually have to fall back on the real-life explanation of "James Marsters in now a cast member on Angel, therefore Spike will remain in LA." :)