Pretty much what the title says. It would be neat if it's just a simple synth I load up that can connect to alsa by itself and whatnot, but if there's a ladspapsap plugin for ardur or something, I'll take that too.

Doesn't need to be great, can be commercial software, should just resemble some kind of piano sound so I can use my keyboard while I'm not on windows.
Everything jack related doesn't seem to work. Not with my midi keyboard, and not with dkpkapkpa either. I used to use jackd a lot years back, and I have no nostalgic feelings about it. If you have something that doesn't require jackd, I'd be very thankful.

Hi, qsynth (fluidsynth) is a midi interface that may use sound fonts. It works well.

I have it installed, but not configured to run only with jackd (qjackctl, sequencer and patchbay).

That being said, I used to use it with rosegarden (midi sequencer/controller), Hydrogen Drums and Ardour(oops, WITH jackd).

There are some very nice FREE soundfonts on the web, All the best, Glenn