I don't know if it's the best one but I've been using CCS64 on my laptop for a while without any problems..
Haven't tested joystick support since I don't have any, but it looks like it supports that:
http://www.computerbrains.com/ccs64/
The are some links to C64 games sites there, and I found some nice classics here as well:
http://www.zzap64.co.uk/c64/c64games1.html
Just tested Ghostbusters and Last Ninja now..
