Anytime I see pinstripe slacks, the only thought that comes to mind is... "Where's the other half of the suit..." It might be just me, anyone else agree?
It really depends on the pants. If they are cut wide, pleated and cuffed, and generally look like they should have a jacket covering the top, then yeah. But if they are slim, flat front, relatively low-waisted and uncuffed, who's to say whether they were from a suit or not? I am wearing a pair cut just like that right now, dark gray flannel with narrow spaced variegated pinstripes from a thrift store HSM suit, and they look really good without the jacket. However, the pinstripes are not very obvious on these. Better choices would be flannels and muted color pinstripes, or more obvious chalkstripes. Avoid navy with thin white beaded pinstripes, the typical "banker's suit" look. Although, I have a nice pair of Polo linen/cotton pants just like that, and they look fine. So, scratch that. Avoid rules instead.