Either/or for the 6XX/58X, they're really about the same. 58X is voiced sliiiiightly warmer with sliiiiightly better bass extension. Really about the same.@jae: 6XX, how does it compare to the 58X?
So I've settled on a plan. Depending answers on the 6XX vs 58X, I'll pick one of those. I'm leaning on the EX5 if I feel the need to buy a dac/amp (I really want to dip my toes by getting one at some point). Both 6XX and 58X are well below my budget so that's pretty good news.