My experience is different because I've never lost a major amount of weight, but I can tell you that I went from 130 to 165 with my first, got back down to 132 and got pregnant immediately, got up to 160 with the second, got back down to low 130's and bounced around a bit in the 130s. Was 137 when I got pregnant with #3, went up to 167, and was down to 132 when he was 7 months old. Now he's 19 months and I'm the thinnest I've ever been!
I think the key is being healthful during your pregnancy. I'm sure with all that you know now, you can keep your pregnancy weight gain a little lower. I'm not one who advocates a 15-lb gain, though I hear a lot of women try for that. I always aimed for 30 lbs. I swam laps (with a kickboard, I'm a lousy swimmer) while I was pregnant with #1, right up until the day before I went into labor, and the weight fell off right away -- I think it helped that I was fit going in. Swimming was great because it made me weightless (so nice at 39 weeks) and it was cool (I was pregnant in August in SoCal).
Maybe track down GuamVixen here on 3FC -- she's pregnant right now I think!