The past few years have seen something of a revival of rye whiskey, but the rye whiskey currently being bottled is different from the rye whiskey of the early part of the 20th Century. The old rye mostly came from Pennsylvania and Maryland while modern rye comes from Kentucky, of course, but there's another substantial difference between the two. Old-style rye had a very high proportion of rye in the mashbill (I believe that I have read somewhere between 70% and 80%), while modern rye tends to have the smallest proportion that distilleries can use and still call the resulting whiskey straight rye (51%). The remainder is corn (probably between 35% and 38%) and malted barley. I have never had any old-time rye, but reason indicates that modern rye would be much more Bourbon-like than the ryes of yore. Which is not to say that modern rye is indistinguishable from modern Bourbon. It is very much its own beast, and one can smell the difference from a mile away.
The reference rye for me is Wild Turkey. This is not to say that it is the best rye whiskey on the market, just that the characteristics that I associate with rye are present in Wild Turkey and that if someone doesn't like Wild Turkey, he doesn't like rye whiskey. Anyway, as I wrote yesterday about Russell's Reserve Rye, it's interesting to compare Wild Turkey to Russell's Reserve. I can tell that they're siblings, but they are very different. Russell's Reserve is refined and smooth; Wild Turkey is brash and exuberant. I like them both.