Wouldn't recommend surveys. You get 50p for most of them (even if they say 'up to £5', the key word is up)
There is no easy way to make loads of money on the internet, you've listed most of the ways possible, and now days you would be surprised how easy it is to get a machinima contract. If you're looking for a fair amount of money, maybe you should look into that.
If you want a little bit of money, complete the surverys for small return, etc. You could even make use of NGU, and sell a prestige hack for money over paypal.
Another way of making a serious amount of money, is buying a JTAG'd xbox. Great return.
And what should I be selling on eBay?
This is strictly internet, therefore I would not be interested in selling stuff I have in physical possession.
You can start with anything, just make sure you're making a profit after postage every time. I remember on the radio a few years back they started off with a brick. They sold the brick and bought something else for a profit, so that and so on. They ended up with about 250 quid! It works if you have the patiences to do it.
My friend uses some survey site, I can PM you the site if you want. He uses a bot to fill out surveys with fake info. He's made arounf $500 in a few months of doing it. He doesn't actually get hard cash, but he gets gift cards off of the site
(I think the site gave him some viruses, but nothing major, and he still made around $500)
Unless you have alot of money to invest the only thing you'll be able to make are really minuscule amounts like $1 for an hour's work or something. Watch out for the scam sites though, all the sites that sound too good to be true are.