Personally I prefer Cubase but thats mostly because I have used it from v2 on the Atari and I use UAD plugins so the native plugs issue isn't so great. Have recently got Logic 8 as well so will report back once I have given it a good try really like it on initial testing but Im leaning far more to Cubase 4.1 (came out last week) than Logic for the time being simply because Im more confortable with it and don't really want to invest the time in learning a new DAW.

As for Ableton I had to use it exclusively for a while recently and while I wouldn't hesitate to recommend it to others Im really not that happy with it as a DAW myself can't really put my finger on why either again I suspect it's just years and years of Cubase use.