For me, I get restless and rarely focus on one list for very long. This results in rarely tabling (due to lack of consistent practice), but I like experimenting and variety, so there is that.
A negative result of this though, is that after almost a year of play, I don't know that I've settled on a specific 'play style, or even that I know what it is'. I try to simply play the fleet I've put together, regardless of whether or not it fits any personal style.
My thoughts are that this may finally have to change with Waves 3-5. There are so many options now, that if I have any interest in competitive play, I'm going to have to settle down and start really looking for that fleet that reflects my thinking and skill.
So, my question is this - how did you find your playstyle and lists that complement it? I talked to some of the San Antonio guys at Regional and I think one of them had been playing the same basic fleet for months with small tweaks here and there. How do you deal with striking that balance between expertise with a list and not getting bored running the same basic fleet over and over?