Ok folks, so you want a Nintendo Wii, and you want to be 100% happy when purchasing from Ebay?
I'll keep it simple :D
1. Check the feedback for recent history of sales of Wii's, this is fundementally the most important thing, if someone is even slightly dodgy it will show in the feedback
2. Check what postal service they use, any service without a tracking number is a no no, I mean you are paying a lot of money for a hard to find item why skimp on the postage?
3. Watch out for postage prices, Parcelforce 48 is £14.99 online, Parcelforce 24 is £18.99 and Special delivery is £19.45 for a wii. Sure allow £1 for packaging but don't get ripped off, ebay and paypal do not charge fees on postage.
4. Ask before you bid if you are not sure, simple really plus if the response is quick then you are good to go. Ebay's feedback system is now great to spot problems and ask the seller for a phone number, anyone upfront enough to give you their landline is going to be good.
5. NEVER EVER EVER take a risk and buy something too good to be true. On occassion a scammer might pop up and stick 99 wii's on for less than retail, now the trade price for wii's are around £168, so please no matter the excuse, it's going to be dodgy! They'll stall you with the 'I'm waiting for a delivery that's been promised in two weeks' etc...and while you wait he sells 20 a day, takes the money and runs...but Paypal usually will spot them first.
6. Consoles from within the EU are fine, seriously, the only difference between the two is the plug, so don't worry, they are all in English and play UK games fine.
7. I sell them too.
8. Don't be scared of ebay :D