I had to ask my DH about this one. Your games consoles will work with the UK tvs, but they might not work with games from the UK. Some 360 games are region coded, some aren't. He says that the best thing to do is try them out to know for sure. Additionally, not a lot of stores will be able to take games from the States for trade-ins. For cords, I got a little converter attachment for my personal dvd player from the States, but I know games consoles take up lots more. He's got a tower for everything in our living room! Any more questions, PM me and I'll ask. Cheesebiscuit's also a gamer, so, she'll have more answers, I'm sure!
I'm not a gamer, I'm a games producer
Basically - You need to get a step up transformer for the 360, don't trust that you can just get a plug adaptor, it will eventually explode or melt, they run hot at the best of times. I always recommend selling 360s before you move because they're a pain and not that expensive to re buy.
You also can't use the RROD exchange service out of frankfurt for a US 360 and it will go at some point, including the new Slims, they don't RROD but they do just stop working, we've had 3 go already. Nearly all games for 360 are region locked to NTSC (UK is PAL). Your MS points are region locked so you can't buy them in store but you can still buy them via the guide.
The original AC adapter that comes with the Nintendo Wii again is not dual voltage. However, you can purchase a 3rd party 110-220 volt ac adapter specifically for the Wii from places like Amazon or use a step up transformer again. Wii games are mostly region locked. This can be gotten around with some googling (bit dodgy).