Can anybody tell me this word--7 letters,all five ...

Aerious...Sequoia...Eutopia

I'd say that "sequoia" is the best answer.  All other words that fit the criteria -- including "aerious" and "eutopia" -- are obscure.  ("Aerious" is interesting, though, because it uses all five vowels in alphabetical order.)

"There are several seven-letter words containing all the vowels, including SEQUOIA, EULOGIA, MIAOUED, ADOULIE, EUCOSIA, EUNOMIA, EUTOPIA, MOINEAU, and DOULEIA. The relatively common French word OISEAU (meaning bird) contains all five vowels, once each. The shortest word with the five vowels occurring in alphabetical order is AERIOUS (airy), which has seven letters."

http://www.fun-with-words.com/word_vowels.html