Auto Meter sells a decent one. A local store around here sells it....and people I know say it works pretty good. I personally woudn't go digital...just because I believe that a standard guage is more reliable. PPE also sells one..but it's a little more expensive. In my opinion...as long as you spend around 150.00.....you'll get a reliable one.
As in style wise? I got the Autometer Ultra lit II in mine and love it! The color change at night is pretty cool and helps in the non "blinding" as well. I know that Automoter and Isspro's are the top 2.
For the extra time and money I think id throw the boost gauge in as well. Incase you want to add a gauge later you could throw a dual pillar pod in and fill the other hole with a sticker or autometer makes a pretty sweet clock.