http://www.lemon64.com/ is a great place to learn about the games.
Atari 2600 controllers work, though some models were sensitive to having stuff plugged into port 1 while the system was on so a lot of 1 player game use port 2. When in doubt, plug your stick in port 1 with the power off. Wico make the best sticks to use IMHO.
The disk drive is painfully slow compared to modern PCs. There is an Epyx Fast Load cart, as well as others which can help and is compatible with a lot of games. Make sure the drive has adequate ventilation when you get one. There are cart games too.
If the video cable you get has red/white/yellow plugs, it is
not video and L/R. It is s-video split into 2 RCA plugs and mono sound.
There are tons of C64 enthusiast sites out there. Many will be various European flavors.