Well, remember that most *nix apps follow the mantra of “do one thing and do it well”. (You probably have a hard time editing with ardour, since that is not what it was generally intended for.)
You probably want several apps working in conjunction to get the same functionality.
And of course there are quite a few soft-synths you can toss into the mix as well, but the programs listed above should provide functionality similar to Ableton Live when used together.