Getting a good computer for audio isn't as hard as it seems (most of the time). Assuming you know what OS you want, I would first take into consideration what you're trying to accomplish. you mentioned using FL, which can only use 4 gigs of ram currently so you don't really more than that (thats what I use, and haven't had any trouble). Then make sure your processor is pretty good. Now depending on what plugins you're going to be using (are we talking a 10mb reverb plugin, or several 40 gig sample libraries?) you'll want a lot of space. You don't have to go overboard or anything, but 500gigs should keep you happy (plus you should get an external as well for backup in general). In terms of a soundcard, get something with a texas instruments (TI) chipset. SIIG and a couple of other companies make them, so feel free to look around (if you want a laptop, chances are you'll need an express card if you are doing more than sequencing). Go after what you'll need (firewire/usb) with the card.
So, which computer do you buy? Can't say, choose what is good for you, I don't even know the budget! If you follow the parameters above though, you should be in good shape. I'd highly recommend microcenter, they have great buys. Anyway, best of luck, hope this helped, and feel free to ask more.
-nocarsgo
