If I had to guess, I'd see Pierre leading off and Furcal batting second. Wherever he's batting, though, with Drew out of LA, I think the hitters behind Furcal won't be good enough to prevent Furcal from running just as much as he did last year. They have a solid lineup, but with the possible exception of Kent (who's aging and may spend as much time on the DL as in the lineup), there aren't really any hitters good enough that a fast player on first would be especially conservative when that hitter's at the plate. So even if Furcal's hitting 2nd or 3rd, I don't think his SB's should change too much.
As for the first/second-half splits, I'm not quite sure to think about it. He's had pretty drastic splits the past two years, and he's been in the league long enough that I'm not sure I'd take his second half as a sign that he's breaking out to a new level. As long as the numbers are there at the end of the year, I'll be happy.