My wife said I could build a new computer today out of the blue!!! Ok, so I pestered her, but she agreed out of the blue

I'm a complete noob at modding, so I'd like to get a new case that I can learn to mod on, and something that will fit my Asetek Antarctica watercooling kit internal (due to arrive Friday, so I'm not sure of it's size). Great cooling is a plus, but something I can mod for even better cooling is a bigger plus
If I should have posted this in the cases section, my mistake, but I figured I'd post here since I'm looking for something I can mod, and I'm not sure what will work.