For the sake of posterity, these are the most epically fun (read ‘high-scoring’) songs that I have found thus far using Audiosurf, sorted by possible score in casual mono (with Iron Mode activated, naturally).
Acperience 1 by Hardfloor – 850,000+
Acperience 5 by Hardfloor – 500,000+
Through the Fire and Flames by DragonForce – 300,000+ (yes, it’s cliche, but it is high scoring and fun)
Map of the Problematique by Muse – 250,000+
Adagio for Cowbells version 1 by DJ AnounymOS – 210,000+
Tip Taps Tip by Halcali – 200,000+
We’re in Heaven by DJ Sammy – ~200,000 (I’m unsure how high this goes, but this is definitely harder than most of the others)
BAWWW version 1 by DJ AnounymOS – 180,000+
CaramellDansen (Speedycake Remix) by Caramell – 140,000+, 190,000+ with other characters
Pics or it didn’t happen :P