Whatever rifle you have in hand. I've taken rabbits with everything from .22lr to
7.62x54R.
Generally, you're taking them at close enough ranges to manage a headshot, so wasted meat is a non-issue.
If I was going to buy something dedicated for rabbits... The lightest weight .22lr single shot I could find. I know a few guys who get those kid-trainer single shot bolts for rabbits, because they're so small and lightweight to pack around in the bush. Length of pull sucks, but you can manage, and you probably will only be firing a couple of shots or so a day, so not like it needs to be comfortable at the shoulder, it just needs to work. They also tend to be cheap, so you're not worried about messing it up, wandering through the scrub.
Cabelas has the Little Badger on sale at the moment for $169.00, which is an "Ok" choice. I got one 5 or 6 years ago. Enjoyed it at first, but then kind of moved on.
Little .410 shotguns make a nice choice for rabbits too, just a bit hard on the ears.
TradeEx has a pile of Husqvarna single shot .22s in stock at the moment, in the $150-$180 range. It would be hard to go wrong with a $180 Husqvarna.