I'm not sure. Part of me wants a .22 Hornet, part of me wants a .204 Ruger, part of me wants a Savage .17HMR with the nifty laminated thumbhole stock, and yet another part of me wants a .243 - but I'm thinking the .17HMR and .204 Ruger are the most realistic options. I doubt I'll be after anything larger than cats any time soon, so those two should suffice.
Who knows... I might just continue to expand my collection of .22's