Another vote for Boyds, I do like there featherweight Thumbhole stock but I put a Prairie Hunter on a Savage 11 and I really like it as well, I put their Classic on a Ruger and didn't like it as much, I have bought about 6 or 7 of them now and they have all been excellent. Good instructions on their sites about which stock will fit your Stevens,
make sure you order the front action bolt as well if you are replacing a synthetic stock on a Savage or a Stevens