Yes, a stop overnight between Jasper and Vancouver is recommended for everyone who hasn't driven the road a zillion times before. If you're taking the Hwy 5 (via Valemount), you're pretty much stuck with Kamloops (unless you want to make a fairly early stop at Clearwater). If you're going via Hwy 93N (Icefields Parkway) and then Hwy 1 (Trans-Canada Hwy), you can choose Golden, Revelstoke, Sicamous, Salmon Arm, or Kamloops (from east to west), depending on how much driving you want to do. I'd recommend Salmon Arm and Revelstoke for places to spend time in. Revelstoke has an excellent railway museum, the fabled Columbia River, and the Micah Dam to explore. Salmon Arm is a small city on the shores of Shuswap Lake and has the long pier, houseboats (free tours daily), a nature reserve, movie theatres, and some shopping and restaurants. (Revelstoke may also have these things, I'm just a bit more familiar with Salmon Arm.)
The drive from Jasper to Kamloops via the Icefields Parkway is well worth doing; the scenery is very nice. The rest of the trip is not as impressive, but it has its moments.