KnoLinux reviews SimplyMEPIS 6.0.4 64 bit and are very, very happy with it. A bunch of screenshots as well.
Read it here
To quote myself, something I never do, “I will be back for the 64 bit when available however, as I am still waiting on a distro that will uncork my boat anchor.” Well, guess what folks? I am happy to say that MEPIS is now my default system and I am happy to be running 64 bit on my not so much of a boat anchor laptop. I haven't really given up much now, as one can add win32codecs if they go here and libdvdcss is installed into the repository. Flash is working with Firefox 2.0, so that seems to have been taken care of by the people at Mepis, which is usually something one loses with 64 bit.