No, emulation should not be legal, it is blatant stealing. You may argue that the games are no longer being sold, bla bla whine whine, but as Nintendo has proven, the companies can always go back and re-sell classic games whenever they feel like it, and free emulation would destroy the profitability of this.
On a slightly different issue, however, I thing that video games (and all copywritten works) should enter the public domain much sooner. 75 years or whatever it is currently is way too long. I think the limit should be 20 years, or something similar. C'mon, people would still be creating things even if they could only have exclusive rights to their works for 20 years or so. Getting filthy rich for the rest of your life because of one good idea you had half a century ago seems ridiculous.
Also, I think public libraries should carry video games. They already carry books, music, movies, and other forms of copywritten work...so why the heck not video games? With everything else they waste our tax money on, would it be so terrible for them to give us free access to video games?