Considering 27" iMac. Can I use it as a TV? I may be considering to get the iMac.

I don't own a TV, but I would love to be able to use it as such. I understand it has a DisplayPort input for these types of purposes.

What would I need to get to get my Wii and analogue TV (PAL) hooked up to this?
The best way to get TV hooked up to a Mac is through a TV Tuner. The best TV Tuners for Mac are by far the EyeTV tuners. The TV tuner could also be used to hook up to your Wii, however that is a bit impractical. Instead consider buying an adapter from RCA to Mini-Display Port to use your iMac as a Monitor for the Wii.