Generally, when they say "anti-fog" they mean "normal", and when they say "thermal" then they actually mean that they won't mist up. If you want to be able to see then go for something with a thermal lense... it's worth it in the long run...
I use JT Flex 7s, because they're roomy enough for my glasses, and don't mist up - though they're a bit more expensive.
I think that Smart Parts are doing a xmas special on green IZEs, which are the same but coloured, but that's £40 plus VAT and postage
Generally the arguments on this board end up being between Dye Invisions and JTs... and the final comments usually end up as "try them all and decide what you like".