Fratton Park for me. The walls outside smelt of piss, and the away end didn't have a roof. Luckily when I went, it was sunshine, but I've heard reports of others getting soaked.
Goodison Park, I'd have to criticise. I'm not having a go at Everton - great club, and Moyes a great manager. It's even a nice ground...but the away section is horrible. Not proper seats, just a long wooden bench. I went in I think it was maybe 2006/2007, so if it's changed now this comment is no longer valid.
St James' Park is great, but it's hard to navigate. As a 15 year old that got the coach up years ago, I was 30 seconds away from missing it and having to spend a night in Newcastle with no money and cross parents. Needs better sign posting and easier access for away fans.