I had to join and replay after seeing this particular topic. The fact is that most well vodkas are made with grain. Strike Skyy, Absolut, Grey Goose, Stoli, Belvedere, Seagram's Vodka off your list of okay drinks.. Chopin and Ciroc, mentioned above, are made from potato and grape, respectively. A simple rule of thumb for vodkas might be to ask for a Polish vodka that is not Belvedere, as Belvedere is the exception to the potato-ruled world of Polish vodka. Three Olives is made from soy, and although I have not found the specific contamination, it has given me horrible headaches and time on my hands and knees from one sip.

Whiskey is made from various grains, but 98% of it is distilled from/through Barley. Scotch is made from malt or barley, so nix that. My sister swears the peat bog scotch is okay, but since I can't confirm or deny that, and I'm sure the companies that make it don't test every individual slice of peat bog for cross contamination, I wouldn't risk it myself.

Bourbon is NOT okay. It is considered bourbon if it is at least 51% corn and distilled for a minimum period of time. But the other 49% is made from water, wheat, barley or rye. Most bourbon brands use wheat.

Gin is double distilled from white grain ethanol, and then distilled through juniper berries or other natural products, depending on brand, thus rendering it closer to safe than most.
As far as I have found, Captain Morgan, Admiral Nelson, Sailor Jerry, and certain other brands of spiced rum are perfectly fine to drink, although I can't say for all spiced rum. This does not include certain specialty brands of the above mentioned, such as Captain Morgan's Tattoo, which is really not okay.

According to the lore of Tequila, it is made with at least 51% Blue Agave, a type of cactus, etc etc etc. Please be aware that if you are not drinking a tequila that says it is 100% Blue Agave, you may have stumbled on a tequila that does in fact contain wheat, rye, barley, malt, etc. Gold Tequilas, such as Jose Cuervo Gold, are often distilled with cane sugar distilled alcohol, and thus should be fine to drink. I would stick to the name brands on this, as it only has to have 51% agave to be called tequila.

Chambourd and Grand Marnier are perfectly fine to drink, at least according to their manufacturers. Certain kinds of liqueurs are more than fine to drink, but liqueurs are too numerous and annoying to list right now, and like everything else, does depend on brand name.

I won't go into beers, as its been done more than adequately above.
Wines are also too numerous for me to get into, but also, not really my area of expertise.