I haven't found good maternity jeans; I'm a size 18-20, mostly due to hips/butt.
I do like Gap's maternity pants (I bought a bunch of them during my last pregnancy and dug them out for this one), but I haven't tried their jeans. Just a simple black flare-leg pant that I wear for work, gardening, whatever.
I also got into yoga pants with my last pregnancy. Looking for another comfy pair for this one. I was going to try Old Navy..We'll see. I can't stand the quality of Motherhood's pants, but it seems like when you're plus size the fit might be worse. Their "regular" sizes look like they might be better made.