Backyard - some great clothing items I use a lot, for BB I especially love the triple picture and the tabletop stuff with the sauce bottles etc. The shark water slide is also a favourite, my sims have a lot of fun on that and it gets placed in public parks.
Vintage Glamour - for me, it's not a favourite and I probably wouldn't miss it if I didn't have it. Sometimes I remember to use the dressing tables but not often.
First Fits - I didn't fancy this one at first and it took me a while to buy it but I gotta say the clothing gets a ton of use in my game. My faves are the boots and trainers but most of the stuff gets used a lot. Surprisingly, it has ended up being one of my favourite kits, certainly my favourite CAS kit.
Country Kitchen - I loved using the items when it first came out but have to admit that I prefer the kitchen stuff from the Cottage Living pack, which is fairly similar but better IMO. But, if you don't have CL you will likely love the pack.