I actually have never played C64 at all, but I have my system with disk drive and a bunch of games on the way as we speak, I can't wait.
I'm big into arcade hardware and doing mods and repairs etc, so I am already anticipating learning some new hardware. Right now I'm watching a lot of ebay videos of playthroughs and reviews of games, I have an unopened Sega pack of arcade hits and a few other games on the way, which I can't wait to open up and play. I would really like to use my C64 for some basic computing as well, I love how people are able to do stuff like run a server (however badly) etc with them. I'm especially inspired since my windows netbook is trash!
I've got a ton of questions since I've never used a C64 yet but I'm just gonna lurk on the forums and try to educate myself first.