YEP. I’ve had the same issues with Gap’s white jeans. I’d suggest trying them on at Old Navy if you can. I’ve noticed the transparency varies from year to year. The pair I have from a few years ago is more opaque than the pair I bought (and returned) last year. I’ve read good reviews of this year’s batch so I ordered them again. The white pairs do seem to always run smaller than Old Navy’s blue denim, but sizing up in white jeans isn’t a horrible idea.
I’m also intrigued by Hue’s jeggings ($40) in white. I’ve heard AMAZING things about the other colors. I think these Curvy Skinny jeans from LOFT ($69.50, take 30% off with FIRSTLOOK) look fantastic too. The ankle length on the hem is the PERFECT length for white jeans. (They’ve got a really subtle dot print so they’re not a true white.) Their true white ones are the same price. Also curious about their Modern Slim version ($69.50 as well). It’s nice that they come in petite/tall sizes.