south padre's beaches comes close to hawaii's on a good day. however on a personal preference, i find the cool blue waters of the pacific more satisfying than the emerald green of the gulf/caribbean. though it isn't even emerald green at galveston/surfside. its dirrty brown! lol!
on good days, it'll be the emerald green. Last time I was there, I was like "wtf, Al Gore did something GOOD for once" then, next day, brown water.