Imo, the M-Audio DMP3 is the best budget pre-amp on the market. It's low noise and will boost your signal. A boosted signal seems to make your in-the-box fx sound better, and you can definately reach broadcast quality with the DMP3.

Next level pre's could be the UA 710, the Grace 101/202 and perhaps the SSL xlogic alpha channel, another step up from that could be the Great River ME1-NV or an SPL channel one mk2 2950.

But you may need more along the way :-)