Best alcohol with Sprite or 7up ?

Vodka and Sprite is good but if you can find a good coconut rum you can make a coconut limeade if you add it to some Sprite and lime juice

Well there is a drink called 7 and 7, which is Seagram7 whiskey and 7up

With 7-Up I like gin. I don't drink Sprite.

Everclear. Hands down. 

Both are lemon-lime soft drinks, which means they mix with almost anything, and they're interchangeable.  That means it doesn't matter which brand you use.  Here are some popular ones with 7Up as the mix....

7 and 7:  Rye (Seagram's Seven) 
Rum Rambler: Rum
Screw Up:  Vodka
Southern 7:  Southern Comfort
Adios Motherf**ker: Rum, vodka, tequila, gin, blue curacao

If you're starting to think 7Up mixes with just about whatever blurs your vision, you're thinking right.

Any American, drinking that stuff wont affect the spirits, in fact it could, however unlikely improve the taste.

Cocktail.......

Vodka. I like Deep Eddy's Lemon Vodka with lemon-lime soda

Bourbon, Jim Beam but any bourbon will do. 
Then there is the old stand-by a 7 and 7
"Pour whiskey into Collins glass filled with ice. Fill to desired level with 7 Up. Stir lightly. A 7 and 7 is a highball cocktail, a mixed alcoholic drink containing Seagram's Seven Crown and 7 Up."

C'est presque la meme chose, prend celui qui est moins cher.