Unfortunately, that's a pretty open ended question.
I don't know much about Linux, but there's a ton of stuff here in the forums and on the wiki about setting things up (though I've only ever looked at the windows versions of those notes, maybe there's not much for Linux?)
The Type OK, is mainly a MAME config issue. One thing you might look into is gathering the required patches and recompiling a custom compile of mame. That would remove those screens completely, add hiscore support, etc.
You might also check out the wah!cade forums (I think this is it
http://www.anti-particle.com/forum_phpbb3/ but I don't use wahcade myself) to see if there's any additional config you can do for it.
Decide on the monitor setup that you'll likely use and you can pick or start designing the layout you'll use.
As for the speakers, if they aren't powered speakers (and even if they are with some speakers) it's likely best just to get a new set (or search craigslist for a set).
I picked up some altec lansing desktop speakers with sub for <40$ and they sound fantastic (even with the speakers mounted in glass ceiling fan lamp shades!), so there's definitely cheap, decent alternatives out there. Then again, you could always find a PC speaker lying around and go that route for the truly authentic arcade feel