4070 for it's relative price/performance and the 4090 for its pure performance
Personally don't think the 4070, even with a little price reduction, is great at all - it is barely an upgrade from the 3070 while retaining prices you'd have likely paid for a 3070 over 3 years ago. Albeit it is a fairly big jump for people on the 1000 series or midrange or lower 2000 series. The 4070 Ti Super is the closest thing to a decent upgrade from the 3070 (in the nVidia line up) performance wise but is £100-150 more expensive than makes sense in that context.
4090 as I've said gets a pass from me, I actually think nVidia underpriced it LOL, the 4080 needs at least 20GB VRAM and at least 15% more performance to justify a £1+K price tag.