Seeing you went for a sensible cheap but OCable 770 chipset which means u are sticking to single GPU set ups all the way for a wee bit of headroom for future upgrades i'd hit a 500-600W 80+ quality PSU for a one time investment ^^ On UK/Europe the usual suspects would be
BeQuiet Pure power 530
Antec High Current Gamer 520
You might want to do some checking on that Antec gamer PSU. Hard just reviewed the 900W model and it can't output anything over 80% of its rated power. First bad Delta sourced review I've seen. There might be something wrong with the gamer line, though I'm sure I've seen good reviews of its 700 (or was it 800W?) cousin.
Casing looks/budget is subjective: some peeps would splash for their dream casings while others would just pick a decent case with reasonable cooling options and hit other areas for performance gains - it's your call i guess ^^
I went with a cheap case, I don't regret it to much. I did have a blow hole installed and used an old 120MM fan from a PSU to help with cooling. I'm thinking about buying a new case with the drive cage turned so that I don't have to remove any cards to change my drives. (I'm always upgrading them, up to nearly 2TBs now spread over 3 drives.)