Best thing to mix with plain smirnoff?!
you are allergic to fruit? wow, that's lame. someone said v8 or clamato but i guess that person doesn't know that tomatoes are fruit. i guess i would mix w/ fake juice, such as kool aid, crystal light, hawaiian punch type powdered drinks because vodka tastes disgusting mixed w/ sodas.
I don't know if you mean Coca-Cola, or any king of carbonated drink, but if not, Mountain Dew Code Red is good. Red Bull, and actually, other liquors are decent, such as Tilt, Sparks, Four Loco, etc. They definitely make the drink stronger but it tastes amazing. It sucks you are allergic to fruit because mixing Vodka with orange juice and making a screwdriver is fun. Another thing you may want to try is Kool-Aid. I have made that mixture before and it wasn't bad. Depending on the quality of your vodka, it may be able to be mixed with anything. Google it. Look for drink recipes that you like. I have an iPhone app that does that easily.
Hope this helps.
Clamato or V8 juice is good - but I like vodka with mostly anything - even Kool-aid.