A lot of people have been talking about launcherpro being the new launcher to use. But really just try them out and decide which one's features you like. Do a google search/forum search of launcherpro and helix and look at what people have to say.
I'd say its between LauncherPro and ADW. Helix isn't even on my radar anymore, but the dev may have made some improvements since I last tried it. I find myself switching back and forth between the two that I listed above quite often.
I prefer launcher pro, much more customizable. Including the main feature I like adding a 5th row on your desktop.
when Im not using launcher pro I use sweeter home2 which is the by far the most customizable, but has the biggest learning curve to its builtin editor. If you try sweeter home dont give up right away hitup youtube and watch how to edit then you will like it much more.
EDIT: as others said all mentioned launchers are free try them all see which fits you best
but for simple easy to use and fast launcher pro is great.