For now, I assume that Haskell is very expressive, but has the speed of most interpreted language,

GHC is a *lot* faster than most interpreted languages :-P Usual caveats, and large handfuls of salt apply. Simon's cheat sheet for getting fast Haskell code: Rule 1: don't use String I/O. Rule 2: Profile your program. Find the inner loop. Look for overloading. Squash. Repeat. Look for laziness. Squash. Repeat. Cheers, Simon