Recommended by me.
I've used WinUAE for years now (ever since my miggy became defunct). I bought AF2011 (and got the free upgrade to 2012 ;-) as I just wanted to, simple as that.
I personally recommend the Amikit install (
http://amikit.amiga.sk/ ).
This updates the look and feel of AmigaOS and adds in a heap of stuff you'd otherwise spend ages finding. The later versions of AF have Amikit directly linked, or it's available for a direct download from the link above.
As to transferring your files/system across, expert advice can be found over at
http://eab.abime.net/ -jd
