Luckily, I got the MyColor gauge cluster that has water temp, oil pressure, and voltage....plus some other stuff from the info center. For a street car/weekend toy I've never been big on having lots-o-guages mounted everywhere and a huge monster tach on the dash. I'm not gonna' duplicate gauges that I already have. For a dedicated race car, having a tach on the dash where you don't have to look down to see it is probably a good thing. I'm going to put a shift light in somewhere, and try to hide it or blend it in. As long as it's bright enough to catch my attention, it doesn't matter where it is.
Even for a N/A application, I think that having a A/F Ratio and Fuel Pressure gauge is useful. You don't need a Boost gauge, but vacuum is also useful information. So, if you're ever planning on going F/I I'd use a combination Boost/Vacuum guage. And if you have an Auto, transmission temp is a good thing to have.