Instead of a font with Greek "symbols" (i.e., extras for occasional use), you presumably want a font with Greek "letters" (i.e., for text). Many of the Slimbach/Adobe families have Greek — Minion, Arno, Warnock, Garamond Premier etc. There are plenty of other good Greek fonts out there as well, many of them without matching Latin.

You can find some fun ones here: http://www.backpacker.gr/fonts.asp?m=1
And some more classical ones here: http://www.greekfontsociety.gr/pages/en_typefaces1.html