I'd recommend ghc, not because its the best distribution, but because its the only one I've used.

Here are the simplest directions I could find that seemed correct:
http://www.mickinator.com/wordpress/?p=31


I'm sure there are directions for hugs, but I haven't used hugs on Ubuntu.

Good luck,
Tim

From: love_pku <love_pku@yeah.net>
To: "beginners@haskell.org" <beginners@haskell.org>
Sent: Tue, March 16, 2010 7:03:30 PM
Subject: [Haskell-beginners] about installation of Haskell



Dear Sir or Madam::

  Sorry to trouble you!

  I am a beginner of Haskell and I just run into problems to install it. So I hope if you can tell me which version of Haskell should I   use for Ubuntu 8.04 operating system..

  Thank you very much!

Best wishes,

 

                                             

                                                Yours juan