Absinthe + pear juice is great. Also absinthe + energy drink of some sorts. Though somewhat good absinthe is necessary for it as fake/cheap brands are really horrible.

Can you recommend some good ones, preferably ones that are available in the US? I've heard good things about North Shore's Sirène...

I can't, sorry. I'm in Europe and drink mostly local ones. But you might check this out for hints http://www.reddit.com/r/absinthe