is your board known to have delicious preamps? i use a Mackie 1604, but i think i'd still wanna use outboard pre's for everything.
no better or worse then a Mackie I imagine...
If I had the $$$ I'd get one fruity pre (probably the Electro Harmonix one http://www.harmony-central.com/Newp/2005/12AY7-Mic-Pre-lg.jpg ) for vocals and acoustic guitars... but then I remember my main mics are a Studio Projects B1 and a SM57... not exactly great mics (though none too shabby for the $$$) so I'd quicker put the money there... if I had it...